天天动听 悬浮歌词(迷你歌词)效果解读
天天动听， 这款Android手机上的音乐播放器，相信不少朋友都曾用过。 不知大家是否注意到，天天动听有一个迷你歌词的特效。
什么效果呢？ 就是不管你切到什么画面， 歌词永远显示，并且可以拖动。 类型QQ音乐，在电脑上播放时显示的歌词效果。
下面先来看一下效果。
这个歌词是在所有界面之上的。
下面我们将这个效果解剖一下， 我认为主要有三个难点：
1. 歌词悬浮在所有页面之上
2. 歌词可以拖动位置
3. 歌词的播放效果 (颜色覆盖)
对于第一点，首先想到的就是 WindowManager ， 这个类可能不少人都用过， 一般用于获取屏幕宽度、高度，那么这次就要利用这个类来让我们的歌词永远置顶。
通过查看API，我们看到，在WindowManager.LayoutParams类中，有好几个属性可以设置View置顶。
TYPE_SYSTEM_OVERLAY
Window type: system overlay windows, which need to be displayed on top of everything else.
TYPE_SYSTEM_ALERT
Window type: system window, such as low power alert.
TYPE_PHONE
These windows are normally placed above all applications, but behind the status bar.
下面我们来测试一下, 通过下面几句代码，就可以让一个View凌驾在所有View之上。
view plaincopy to clipboardprint?
01.WindowManager wm = (WindowManager)getApplicationContext().getSystemService(WINDOW_SERVICE);
02.WindowManager.LayoutParams params = new WindowManager.LayoutParams();
03.params.type = WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY;
04.
05.params.width = WindowManager.LayoutParams.WRAP_CONTENT;
06.params.height = WindowManager.LayoutParams.WRAP_CONTENT;
07.
08.TextView tv = new TextView(this);
09.wm.addView(tv, params);
WindowManager wm = (WindowManager)getApplicationContext().getSystemService(WINDOW_SERVICE);
WindowManager.LayoutParams params = new WindowManager.LayoutParams();
params.type = WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY;
params.width = WindowManager.LayoutParams.WRAP_CONTENT;
params.height = WindowManager.LayoutParams.WRAP_CONTENT;
TextView tv = new TextView(this);
wm.addView(tv, params);
这边需要注意的是， WindowManager也是通过 getSystemService 来获取，但必须先 getApplicationContext， 否则就无效了。
直接WindowManager wm = (WindowManager)getSystemService(WINDOW_SERVICE); 这样是无效的 ！！
还有一点就是，别忘了在Manifest.xml中添加权限：
view plaincopy to clipboardprint?
01.<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
现在我们这样做，我们已经可以让歌词永远置顶了。 但是不要得意，现在这样，结果是我们TextView在最顶层了， 然后你就会发现，页面上什么操作都不能做了， 在TextView下面的任何东西，你都点不了。
为了解决这个，我们必须加上flags参数，让当前的View失去焦点，从而让后面的页面获得焦点。代码如下：
view plaincopy to clipboardprint?
01.params.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL | LayoutParams.FLAG_NOT_FOCUSABLE;
params.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL | LayoutParams.FLAG_NOT_FOCUSABLE;
加上这一句就可以了。
好了，下面要处理的，就是让歌词可以移动。应该如何做呢？
我们知道，想要让一个View对象在页面上可以移动，只要实现其onTouchEvent事件即可。
--------------------------------------------
下面开始实现第二步： 歌词移动！
首先我们自定义一个TextView类：MyTextView， 该类继承自TextView， 并实现其中的onTouchEvent方法，来看一下代码：
view plaincopy to clipboardprint?
01.@Override
02.public boolean onTouchEvent(MotionEvent event) {
03. //触摸点相对于屏幕左上角坐标
04. x = event.getRawX();
05. y = event.getRawY() - TOOL_BAR_HIGH;
06. Log.d(TAG, "------X: "+ x +"------Y:" + y);
07.
08. switch(event.getAction()) {
09. case MotionEvent.ACTION_DOWN:
10. startX = event.getX();
11. startY = event.getY();
12. break;
13. case MotionEvent.ACTION_MOVE:
14. updatePosition();
15. break;
16. case MotionEvent.ACTION_UP:
17. updatePosition();
18. startX = startY = 0;
19. break;
20. }
21.
22. return true;
23.}
24.//更新浮动窗口位置参数
25. private void updatePosition(){
26. // View的当前位置
27. params.x = (int)( x - startX);
28. params.y = (int) (y - startY);
29. wm.updateViewLayout(this, params);
30. }
@Override
public boolean onTouchEvent(MotionEvent event) {
//触摸点相对于屏幕左上角坐标
x = event.getRawX();
y = event.getRawY() - TOOL_BAR_HIGH;
Log.d(TAG, "------X: "+ x +"------Y:" + y);
switch(event.getAction()) {
case MotionEvent.ACTION_DOWN:
startX = event.getX();
startY = event.getY();
break;
case MotionEvent.ACTION_MOVE:
updatePosition();
break;
case MotionEvent.ACTION_UP:
updatePosition();
startX = startY = 0;
break;
}
return true;
}
//更新浮动窗口位置参数
private void updatePosition(){
// View的当前位置
params.x = (int)( x - startX);
params.y = (int) (y - startY);
wm.updateViewLayout(this, params);
}
其中getRawX、getRawY用于获取触摸点离屏幕左上角的距离。 而getX、getY用于获取触摸点离textView左上角的距离.
两者相减，就是View左上角的坐标了。
另外需要注意的是，在显示View这个View的时候，需要正确指定View的x,y坐标，否则拖动时会错位。
view plaincopy to clipboardprint?
01.WindowManager wm = (WindowManager)getApplicationContext().getSystemService(WINDOW_SERVICE);
02. WindowManager.LayoutParams params = MyTextView.params;
03.
04. params.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT | WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY;
05. params.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL | LayoutParams.FLAG_NOT_FOCUSABLE;
06.
07. params.width = WindowManager.LayoutParams.FILL_PARENT;
08. params.height = WindowManager.LayoutParams.WRAP_CONTENT;
09. params.alpha = 80;
10.
11. params.gravity=Gravity.LEFT|Gravity.TOP;
12. //以屏幕左上角为原点，设置x、y初始值
13. params.x = 0;
14. params.y = 0;
15.
16. tv = new MyTextView(TopFrame.this);
17. wm.addView(tv, params);
WindowManager wm = (WindowManager)getApplicationContext().getSystemService(WINDOW_SERVICE);
WindowManager.LayoutParams params = MyTextView.params;
params.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT | WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY;
params.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL | LayoutParams.FLAG_NOT_FOCUSABLE;
params.width = WindowManager.LayoutParams.FILL_PARENT;
params.height = WindowManager.LayoutParams.WRAP_CONTENT;
params.alpha = 80;
params.gravity=Gravity.LEFT|Gravity.TOP;
//以屏幕左上角为原点，设置x、y初始值
params.x = 0;
params.y = 0;
tv = new MyTextView(TopFrame.this);
wm.addView(tv, params);
其中下面三句是关键：
view plaincopy to clipboardprint?
01.params.gravity=Gravity.LEFT|Gravity.TOP;
02. //以屏幕左上角为原点，设置x、y初始值
03.params.x = 0;
04.params.y = 0;
params.gravity=Gravity.LEFT|Gravity.TOP;
//以屏幕左上角为原点，设置x、y初始值
params.x = 0;
params.y = 0;
现在这样的话，就可以实现View的移动了。
--------------------------------------------
下面实现第三步： 歌词的播放效果。
那么本例仅仅做一个循环， 实际音乐播放器要复杂些，需要根据歌剧的长度及时间间隔，来计算歌词的覆盖速度， 再根据这个速度来覆盖歌词，呈现给用户。
要实现歌词播放的效果，需要用到画笔Paint， 还要用到Shader， 还有一个就是UI刷新的问题。
一起来看下代码：
view plaincopy to clipboardprint?
01.@Override
02.protected void onDraw(Canvas canvas) {
03. // TODO Auto-generated method stub
04. super.onDraw(canvas);
05. float1 += 0.001f;
06. float2 += 0.001f;
07.
08. if(float2 > 1.0){
09. float1 = 0.0f;
10. float2 = 0.01f;
11. }
12. this.setText("");
13. float len = this.getTextSize() * text.length();
14. Shader shader = new LinearGradient(0, 0, len, 0,
15. new int[] { Color.YELLOW, Color.RED }, new float[]{float1, float2},
16. TileMode.CLAMP);
17. Paint p = new Paint();
18. p.setShader(shader);
19. // 下面这句才控制歌词大小
20. p.setTextSize(20f);
21. p.setTypeface(Typeface.DEFAULT_BOLD);
22. //此处x,y坐标也要注意，尤其是y坐标，要与字体大小协调
23. canvas.drawText(text, 0, 20, p);
24.
25.}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
float1 += 0.001f;
float2 += 0.001f;
if(float2 > 1.0){
float1 = 0.0f;
float2 = 0.01f;
}
this.setText("");
float len = this.getTextSize() * text.length();
Shader shader = new LinearGradient(0, 0, len, 0,
new int[] { Color.YELLOW, Color.RED }, new float[]{float1, float2},
TileMode.CLAMP);
Paint p = new Paint();
p.setShader(shader);
// 下面这句才控制歌词大小
p.setTextSize(20f);
p.setTypeface(Typeface.DEFAULT_BOLD);
//此处x,y坐标也要注意，尤其是y坐标，要与字体大小协调
canvas.drawText(text, 0, 20, p);
}
再加上handler, 让他每隔3毫秒画一次， 就有了这个歌词播放的效果。
view plaincopy to clipboardprint?
01.private Runnable update = new Runnable() {
02. public void run() {
03. MyTextView.this.update();
04. handler.postDelayed(update, 3);
05. }
06. };
07.
08.private void update(){
09. postInvalidate();
10.}
private Runnable update = new Runnable() {
public void run() {
MyTextView.this.update();
handler.postDelayed(update, 3);
}
};
private void update(){
postInvalidate();
}
好了，下面发一下效果图：
最后附上整个工程的代码：(一个就两个类，一个布局文件)
AndroidManifest.xml
view plaincopy to clipboardprint?
01.<?xml version="1.0" encoding="utf-8"?>
02.<manifest xmlns:android="http://schemas.android.com/apk/res/android"
03. package="com.yfz"
04. android:versionCode="1"
05. android:versionName="1.0">
06. <application android:icon="@drawable/icon" android:label="@string/app_name">
07. <activity android:name=".TopFrame"
08. android:label="@string/app_name">
09. <intent-filter>
10. <action android:name="android.intent.action.MAIN" />
11. <category android:name="android.intent.category.LAUNCHER" />
12. </intent-filter>
13. </activity>
14. </application>
15.
16. <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
17. <uses-sdk android:minSdkVersion="8"></uses-sdk>
18.</manifest>
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.yfz"
android:versionCode="1"
android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".TopFrame"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
<uses-sdk android:minSdkVersion="8"></uses-sdk>
</manifest>
main.xml
view plaincopy to clipboardprint?
01.<?xml version="1.0" encoding="utf-8"?>
02.<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
03. android:orientation="vertical"
04. android:layout_width="fill_parent"
05. android:layout_height="fill_parent"
06. >
07. <Button
08. android:id="@+id/bt"
09. android:text=" 点我试试"
10. android:layout_width = "wrap_content"
11. android:layout_height="wrap_content"
12. android:layout_gravity="center"
13. />
14.</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Button
android:id="@+id/bt"
android:text=" 点我试试"
android:layout_width = "wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
/>
</LinearLayout>
TopFrame.java
view plaincopy to clipboardprint?
01.package com.yfz;
02.import com.yfz.view.MyTextView;
03.import android.app.Activity;
04.import android.graphics.Rect;
05.import android.os.Bundle;
06.import android.view.Gravity;
07.import android.view.View;
08.import android.view.WindowManager;
09.import android.view.View.OnClickListener;
10.import android.view.WindowManager.LayoutParams;
11.import android.widget.Button;
12.public class TopFrame extends Activity {
13. /** Called when the activity is first created. */
14. @Override
15. public void onCreate(Bundle savedInstanceState) {
16. super.onCreate(savedInstanceState);
17. setContentView(R.layout.main);
18. Button button = (Button) findViewById(R.id.bt);
19.
20. button.setOnClickListener(onclick);
21. }
22.
23. private MyTextView tv = null;
24.
25. OnClickListener onclick = new OnClickListener() {
26.
27. @Override
28. public void onClick(View v) {
29. if(tv != null && tv.isShown()){
30. WindowManager wm = (WindowManager)getApplicationContext().getSystemService(TopFrame.this.WINDOW_SERVICE);
31. wm.removeView(tv);
32. }
33. show();
34.
35. }
36. };
37.
38.
39. private void show(){
40. Rect frame = new Rect();
41. getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
42. MyTextView.TOOL_BAR_HIGH = frame.top;
43.
44. WindowManager wm = (WindowManager)getApplicationContext().getSystemService(WINDOW_SERVICE);
45. WindowManager.LayoutParams params = MyTextView.params;
46.
47. params.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT | WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY;
48. params.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL | LayoutParams.FLAG_NOT_FOCUSABLE;
49.
50. params.width = WindowManager.LayoutParams.FILL_PARENT;
51. params.height = WindowManager.LayoutParams.WRAP_CONTENT;
52. params.alpha = 80;
53.
54. params.gravity=Gravity.LEFT|Gravity.TOP;
55. //以屏幕左上角为原点，设置x、y初始值
56. params.x = 0;
57. params.y = 0;
58.
59. tv = new MyTextView(TopFrame.this);
60. wm.addView(tv, params);
61. }
62. @Override
63. protected void onDestroy() {
64. super.onDestroy();
65. }
66.}
package com.yfz;
import com.yfz.view.MyTextView;
import android.app.Activity;
import android.graphics.Rect;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.WindowManager;
import android.view.View.OnClickListener;
import android.view.WindowManager.LayoutParams;
import android.widget.Button;
public class TopFrame extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button = (Button) findViewById(R.id.bt);
button.setOnClickListener(onclick);
}
private MyTextView tv = null;
OnClickListener onclick = new OnClickListener() {
@Override
public void onClick(View v) {
if(tv != null && tv.isShown()){
WindowManager wm = (WindowManager)getApplicationContext().getSystemService(TopFrame.this.WINDOW_SERVICE);
wm.removeView(tv);
}
show();
}
};
private void show(){
Rect frame = new Rect();
getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
MyTextView.TOOL_BAR_HIGH = frame.top;
WindowManager wm = (WindowManager)getApplicationContext().getSystemService(WINDOW_SERVICE);
WindowManager.LayoutParams params = MyTextView.params;
params.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT | WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY;
params.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL | LayoutParams.FLAG_NOT_FOCUSABLE;
params.width = WindowManager.LayoutParams.FILL_PARENT;
params.height = WindowManager.LayoutParams.WRAP_CONTENT;
params.alpha = 80;
params.gravity=Gravity.LEFT|Gravity.TOP;
//以屏幕左上角为原点，设置x、y初始值
params.x = 0;
params.y = 0;
tv = new MyTextView(TopFrame.this);
wm.addView(tv, params);
}
@Override
protected void onDestroy() {
super.onDestroy();
}
}
MyTextView.java
view plaincopy to clipboardprint?
01.package com.yfz.view;
02.import android.content.Context;
03.import android.graphics.Canvas;
04.import android.graphics.Color;
05.import android.graphics.LinearGradient;
06.import android.graphics.Paint;
07.import android.graphics.Rect;
08.import android.graphics.Shader;
09.import android.graphics.Typeface;
10.import android.graphics.Shader.TileMode;
11.import android.os.Handler;
12.import android.os.Message;
13.import android.util.Log;
14.import android.view.MotionEvent;
15.import android.view.View;
16.import android.view.WindowManager;
17.import android.widget.TextView;
18.import android.widget.Toast;
19.public class MyTextView extends TextView {
20. private final String TAG = MyTextView.class.getSimpleName();
21.
22. public static int TOOL_BAR_HIGH = 0;
23. public static WindowManager.LayoutParams params = new WindowManager.LayoutParams();
24. private float startX;
25. private float startY;
26. private float x;
27. private float y;
28.
29. private String text;
30.
31. WindowManager wm = (WindowManager)getContext().getApplicationContext().getSystemService(getContext().WINDOW_SERVICE);
32.
33. public MyTextView(Context context) {
34. super(context);
35. text = "世上只有妈妈好,有妈的孩子像块宝";
36. this.setBackgroundColor(Color.argb(90, 150, 150, 150));
37. // 下面这句话在此并不是控制歌词大小，仅仅是为了控制背景大小，如果不设置的话，Paint字体大时会被遮挡
38. this.setTextSize(20f);
39. handler = new Handler();
40. handler.post(update);
41. }
42. @Override
43. public boolean onTouchEvent(MotionEvent event) {
44. //触摸点相对于屏幕左上角坐标
45. x = event.getRawX();
46. y = event.getRawY() - TOOL_BAR_HIGH;
47. Log.d(TAG, "------X: "+ x +"------Y:" + y);
48.
49. switch(event.getAction()) {
50. case MotionEvent.ACTION_DOWN:
51. startX = event.getX();
52. startY = event.getY();
53. break;
54. case MotionEvent.ACTION_MOVE:
55. updatePosition();
56. break;
57. case MotionEvent.ACTION_UP:
58. updatePosition();
59. startX = startY = 0;
60. break;
61. }
62.
63. return true;
64. }
65.
66. @Override
67. protected void onDraw(Canvas canvas) {
68. // TODO Auto-generated method stub
69. super.onDraw(canvas);
70. float1 += 0.001f;
71. float2 += 0.001f;
72.
73. if(float2 > 1.0){
74. float1 = 0.0f;
75. float2 = 0.01f;
76. }
77. this.setText("");
78. float len = this.getTextSize() * text.length();
79. Shader shader = new LinearGradient(0, 0, len, 0,
80. new int[] { Color.YELLOW, Color.RED }, new float[]{float1, float2},
81. TileMode.CLAMP);
82. Paint p = new Paint();
83. p.setShader(shader);
84. // 下面这句才控制歌词大小
85. p.setTextSize(20f);
86. p.setTypeface(Typeface.DEFAULT_BOLD);
87. //此处x,y坐标也要注意，尤其是y坐标，要与字体大小协调
88. canvas.drawText(text, 0, 20, p);
89.
90. }
91.
92. private Runnable update = new Runnable() {
93. public void run() {
94. MyTextView.this.update();
95. handler.postDelayed(update, 3);
96. }
97. };
98.
99. private void update(){
100. postInvalidate();
101. }
102.
103. private float float1 = 0.0f;
104. private float float2 = 0.01f;
105.
106. private Handler handler;
107. //更新浮动窗口位置参数
108. private void updatePosition(){
109. // View的当前位置
110. params.x = (int)( x - startX);
111. params.y = (int) (y - startY);
112. wm.updateViewLayout(this, params);
113. }
114.}
package com.yfz.view;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Shader;
import android.graphics.Typeface;
import android.graphics.Shader.TileMode;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.TextView;
import android.widget.Toast;
public class MyTextView extends TextView {
private final String TAG = MyTextView.class.getSimpleName();
public static int TOOL_BAR_HIGH = 0;
public static WindowManager.LayoutParams params = new WindowManager.LayoutParams();
private float startX;
private float startY;
private float x;
private float y;
private String text;
WindowManager wm = (WindowManager)getContext().getApplicationContext().getSystemService(getContext().WINDOW_SERVICE);
public MyTextView(Context context) {
super(context);
text = "世上只有妈妈好,有妈的孩子像块宝";
this.setBackgroundColor(Color.argb(90, 150, 150, 150));
// 下面这句话在此并不是控制歌词大小，仅仅是为了控制背景大小，如果不设置的话，Paint字体大时会被遮挡
this.setTextSize(20f);
handler = new Handler();
handler.post(update);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
//触摸点相对于屏幕左上角坐标
x = event.getRawX();
y = event.getRawY() - TOOL_BAR_HIGH;
Log.d(TAG, "------X: "+ x +"------Y:" + y);
switch(event.getAction()) {
case MotionEvent.ACTION_DOWN:
startX = event.getX();
startY = event.getY();
break;
case MotionEvent.ACTION_MOVE:
updatePosition();
break;
case MotionEvent.ACTION_UP:
updatePosition();
startX = startY = 0;
break;
}
return true;
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
float1 += 0.001f;
float2 += 0.001f;
if(float2 > 1.0){
float1 = 0.0f;
float2 = 0.01f;
}
this.setText("");
float len = this.getTextSize() * text.length();
Shader shader = new LinearGradient(0, 0, len, 0,
new int[] { Color.YELLOW, Color.RED }, new float[]{float1, float2},
TileMode.CLAMP);
Paint p = new Paint();
p.setShader(shader);
// 下面这句才控制歌词大小
p.setTextSize(20f);
p.setTypeface(Typeface.DEFAULT_BOLD);
//此处x,y坐标也要注意，尤其是y坐标，要与字体大小协调
canvas.drawText(text, 0, 20, p);
}
private Runnable update = new Runnable() {
public void run() {
MyTextView.this.update();
handler.postDelayed(update, 3);
}
};
private void update(){
postInvalidate();
}
private float float1 = 0.0f;
private float float2 = 0.01f;
private Handler handler;
//更新浮动窗口位置参数
private void updatePosition(){
// View的当前位置
params.x = (int)( x - startX);
params.y = (int) (y - startY);
wm.updateViewLayout(this, params);
}
}
好了，就讲这么多。
