一个有关Android的页面的跳转的问题
想实现两个桌面之间的跳转 但是运行的时候程序报错了！
这个桌面是ImageButton组件做的，想实现按下按钮就可以跳转到这个页面
可是当程序运行的时候报错了！
但是在logcat中报错是空指针！
这个是主程序代码：
package com.IWeekly2;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
public class Main extends Activity {
private ImageButton btnView,
btnRead,
btnPictrue,
btnShopping,
btnSending,
btnSave,
btnShare;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
setupViewComponent();
}
private void setupViewComponent(){
btnView = (ImageButton)findViewById(R.id.btnView);
btnRead = (ImageButton)findViewById(R.id.btnRead);
btnPictrue = (ImageButton)findViewById(R.id.btnPictrue);
btnShopping = (ImageButton)findViewById(R.id.btnShopping);
btnSending = (ImageButton)findViewById(R.id.btnSending);
btnSave = (ImageButton)findViewById(R.id.btnSave);
btnShare = (ImageButton)findViewById(R.id.btnShare);
btnView.setOnClickListener(btnViewLis);
btnRead.setOnClickListener(btnReadLis);
btnPictrue.setOnClickListener(btnPictrueLis);
btnShopping.setOnClickListener(btnShoppingLis);
btnSending.setOnClickListener(btnSendingLis);
btnSave.setOnClickListener(btnSaveLis);
btnShare.setOnClickListener(btnShareLis);
}
private Button.OnClickListener btnViewLis = new Button.OnClickListener(){
public void onClick(View v){
Intent v1 = new Intent();
v1.setClass(Main.this,TabMain.class);
startActivity(v1);
}
};
private Button.OnClickListener btnReadLis = new Button.OnClickListener(){
public void onClick(View v){
Intent v1 = new Intent();
v1.setClass(Main.this,TabMain.class);
startActivity(v1);
}
};
private Button.OnClickListener btnPictrueLis = new Button.OnClickListener(){
public void onClick(View v){
Intent v1 = new Intent();
v1.setClass(Main.this,TabMain.class);
startActivity(v1);
}
};
private Button.OnClickListener btnShoppingLis = new Button.OnClickListener(){
public void onClick(View v){
Intent v1 = new Intent();
v1.setClass(Main.this,TabMain.class);
startActivity(v1);
}
};
private Button.OnClickListener btnSendingLis = new Button.OnClickListener(){
public void onClick(View v){
Intent v1 = new Intent();
v1.setClass(Main.this,TabMain.class);
startActivity(v1);
}
};
private Button.OnClickListener btnSaveLis = new Button.OnClickListener(){
public void onClick(View v){
Intent v1 = new Intent();
v1.setClass(Main.this,TabMain.class);
startActivity(v1);
}
};
private Button.OnClickListener btnShareLis = new Button.OnClickListener(){
public void onClick(View v){
Intent v1 = new Intent();
v1.setClass(Main.this,TabMain.class);
startActivity(v1);
}
};
}
这个是AndroidManifest.xml代码:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.IWeekly2"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="9" />
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".Main"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".TabMain"/>
<activity android:name=".First"/>
<activity android:name=".Second"/>
<activity android:name=".Third"/>
<activity android:name=".Fourth"/>
<activity android:name=".Fifth"/>
</application>
</manifest>
这个是出错的代码:
package com.IWeekly2;
import android.app.TabActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.GestureDetector.OnGestureListener;
import android.view.View.OnTouchListener;
import android.widget.LinearLayout;
import android.widget.TabHost;
import android.widget.TabWidget;
import android.widget.TextView;
import android.widget.Toast;
public class TabMain extends TabActivity implements OnTouchListener, OnGestureListener {
private static final int FLING_MIN_DISTANCE = 20;
private static final int FLING_MIN_VELOCITY = 0;
TabHost tabHost;
GestureDetector mGestureDetector;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.tabmain);
mGestureDetector = new GestureDetector(this);
LinearLayout ll=(LinearLayout)findViewById(R.id.linew);
ll.setOnTouchListener(this);
ll.setLongClickable(true);
tabHost = getTabHost();
tabHost.setup();
Intent intent1 = new Intent(TabMain.this, First.class);
createTab("消息", intent1);
Intent intent2 = new Intent(TabMain.this, Second.class);
createTab("聊天", intent2);
Intent intent3 = new Intent(TabMain.this, Third.class);
createTab("通讯录", intent3);
Intent intent4 = new Intent(TabMain.this, Fourth.class);
createTab("邮箱", intent4);
Intent intent5 = new Intent(TabMain.this, Fifth.class);
createTab("单点登录", intent5);
TabWidget tabWidget = tabHost.getTabWidget();
int count = tabWidget.getChildCount();
tabHost.setCurrentTab(0);
}
private void createTab(String text, Intent intent) {
tabHost.addTab(tabHost.newTabSpec(text).setIndicator(
createTabView(text)).setContent(intent));
}
private View createTabView(String text) {
View view = LayoutInflater.from(this).inflate(R.layout.tab_indicator,
null);
TextView tv = (TextView) view.findViewById(R.id.tv_tab);
tv.setText(text);
return view;
}
@Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
Log.i("touch","touch");
return mGestureDetector.onTouchEvent(event);
}
@Override
public boolean onDown(MotionEvent e) {
// TODO Auto-generated method stub
return false;
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY) {
int total=tabHost.getTabWidget().getChildCount();
int current=tabHost.getCurrentTab();
// TODO Auto-generated method stub
if (e1.getX()-e2.getX() > FLING_MIN_DISTANCE
&& Math.abs(velocityX) > FLING_MIN_VELOCITY) {
// Fling left
Toast.makeText(this, "向左手势", Toast.LENGTH_SHORT).show();
tabHost.setCurrentTab(current-1<0?0:current-1);
} else if (e2.getX()-e1.getX() > FLING_MIN_DISTANCE
&& Math.abs(velocityX) > FLING_MIN_VELOCITY) {
// Fling right
tabHost.setCurrentTab(current+1>total?total-1:current+1);
Toast.makeText(this, "向右手势", Toast.LENGTH_SHORT).show();
}
return false;
}
@Override
public void onLongPress(MotionEvent e) {
// TODO Auto-generated method stub
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
float distanceY) {
// TODO Auto-generated method stub
return false;
}
@Override
public void onShowPress(MotionEvent e) {
// TODO Auto-generated method stub
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
// TODO Auto-generated method stub
return false;
}
}
求大牛帮忙指点!谢谢了
[解决办法]
你那些控件是在 R.layout.main 这个xml里面的吗
[解决办法]
btnView.setOnClickListener(btnViewLis);
这行出的错吧，换成View.OnClickListener吧，ImageButton不是Button的子类
[解决办法]
Main类的setupViewComponent()函数的38行里有null值，仔细检查下，另外你的代码命名啥的太不规范了，建议你好好写写。
[解决办法]
android:layout_height="wrap_content"
android:src="@drawable/share"
android:paddingTop="4dp"
android:paddingBottom="4dp"
android:paddingLeft="4dp"
android:paddingRight="4dp"
/>
