API Demos 2.2 研读笔记（11）——SetWallpaper, Translucent和TranslucentBlur
SetWallpaper
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WallpaperManager是管理wallpaper的主要类，通过它我们可获取当前系统壁纸、设置壁纸等等。
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示例中的主要代码：
package com.example.android.apis.app;// Need the following import to get access to the app resources, since this// class is in a sub-package.import com.example.android.apis.R;import java.io.IOException;import android.app.Activity;import android.app.WallpaperManager;import android.graphics.Color;import android.graphics.PorterDuff;import android.graphics.drawable.Drawable;import android.os.Bundle;import android.view.View;import android.view.WindowManager;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.ImageView;public class SetWallpaperActivity extends Activity { final static private int[] mColors = {Color.BLUE, Color.GREEN, Color.RED, Color.LTGRAY, Color.MAGENTA, Color.CYAN, Color.YELLOW, Color.WHITE}; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.wallpaper_2); // 1.获取与给定Context关联的WallpaperManager final WallpaperManager wallpaperManager = WallpaperManager.getInstance(this); // 2.获取当前系统壁纸 final Drawable wallpaperDrawable = wallpaperManager.getDrawable(); final ImageView imageView = (ImageView) findViewById(R.id.imageview); imageView.setDrawingCacheEnabled(true); imageView.setImageDrawable(wallpaperDrawable); Button randomize = (Button) findViewById(R.id.randomize); randomize.setOnClickListener(new OnClickListener() { public void onClick(View view) {<style name="Theme.Translucent"><item name="android:windowIsTranslucent">true</item> <item name="android:windowBackground">@drawable/translucent_background</item> <item name="android:windowNoTitle">true</item> <item name="android:colorForeground">#fff</item> </style>
? int mColor = (int) Math.floor(Math.random() * mColors.length); // 3.对壁纸进行修改 wallpaperDrawable.setColorFilter(mColors[mColor], PorterDuff.Mode.MULTIPLY); imageView.setImageDrawable(wallpaperDrawable); imageView.invalidate(); } }); Button setWallpaper = (Button) findViewById(R.id.setwallpaper); setWallpaper.setOnClickListener(new OnClickListener() { public void onClick(View view) { try { // 4.设置壁纸 wallpaperManager.setBitmap(imageView.getDrawingCache()); finish(); } catch (IOException e) { e.printStackTrace(); } } }); }}?
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Translucent
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设置window背景为半透明状态。在AndroidManifest.xml中为window配置半透明背景的theme。theme在xml文件中配置。
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1. 通过继承android:style/Theme.Translucent实现。
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<style name="Theme.Translucent" parent="android:style/Theme.Translucent"> <item name="android:windowBackground">@drawable/translucent_background</item> <item name="android:windowNoTitle">true</item> <item name="android:colorForeground">#fff</item></style>
2. 通过设置android:windowIsTranslucent为true实现。
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<style name="Theme.Translucent"> <item name="android:windowIsTranslucent">true</item> <item name="android:windowBackground">@drawable/translucent_background</item> <item name="android:windowNoTitle">true</item> <item name="android:colorForeground">#fff</item></style>
如果同时android:windowBackground为白色时，就是全透明的效果了。
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TranslucentBlur
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设置window背景为半透明状态并且被掩盖的Activity为模糊状。
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主要相关代码：
先设置当前window的背景为半透明状态。然后设置底下的window为模糊状。在setContentView之前调用。
// Have the system blur any windows behind this one. getWindow().setFlags(WindowManager.LayoutParams.FLAG_BLUR_BEHIND, WindowManager.LayoutParams.FLAG_BLUR_BEHIND);