Android4.0上添加截屏快捷方式

拿到Samsung的7寸平板，是3.x系统，在状态栏上多了个截屏按钮，拿到Galaxy Notes 10.1，该功能更是不可删除的添加在状态栏，既然如此，我们今天在我们平板上也添加上该按键，实现简单的快捷截屏功能，而不是按POWER和VOL-进行。

在Android4.0源码的frameworks/base/packages/SystemUI/res/drawable-mdpi/目录下添加ic_sysbar_screenshot.png文件，图片如下：





该图片的背景是透明的PNG文件。
接下来修改frameworks/base/packages/SystemUI/res/layout-sw600dp/status_bar.xml文件，在



android:layout_width="80dip"

android:layout_height="match_parent"

android:src="@drawable/ic_sysbar_screenshot"

android:contentDescription="@string/accessibility_screenshot"

systemui:glowBackground="@drawable/ic_sysbar_highlight"

/>

接下来修改frameworks/base/packages/SystemUI/res/values/strings.xml文件，添加如下内容：

ScreenShot

至此，重新编译烧录源码，在状态栏上会多出截屏图标，接下来需要继续实现截屏功能，查看了frameworks里的源码，找到了frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java文件里有可参考的片断，故继续修改frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/tablet/TabletStatusBar.java文件，相应的添加如下内容：

import android.os.Messenger;

import android.content.ComponentName;

import android.content.ServiceConnection;

在View mRecentButton;后面添加View mScreenshotButton;语句。

在mRecentButton.setOnClickListener(mOnClickListener);后添加如下内容：

mScreenshotButton = mNavigationArea.findViewById(R.id.my_screenshot);

mScreenshotButton.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

mHandler.postDelayed(mScreenshotChordLongPress,

ViewConfiguration.getGlobalActionKeyTimeout());

}

});

接下来在public int getStatusBarHeight() {前添加如下内容：

private final Runnable mScreenshotChordLongPress = new Runnable() {

public void run() {

takeScreenshot();

}

};

final Object mScreenshotLock = new Object();

ServiceConnection mScreenshotConnection = null;

final Runnable mScreenshotTimeout = new Runnable() {

@Override public void run() {

synchronized (mScreenshotLock) {

if (mScreenshotConnection != null) {

mContext.unbindService(mScreenshotConnection);

mScreenshotConnection = null;

}

}

}

};

// Assume this is called from the Handler thread.

private void takeScreenshot() {

synchronized (mScreenshotLock) {

if (mScreenshotConnection != null) {

return;

}

ComponentName cn = new ComponentName("com.android.systemui",

"com.android.systemui.screenshot.TakeScreenshotService");

Intent intent = new Intent();

intent.setComponent(cn);

ServiceConnection conn = new ServiceConnection() {

@Override

public void onServiceConnected(ComponentName name, IBinder service) {

synchronized (mScreenshotLock) {

if (mScreenshotConnection != this) {

return;

}

Messenger messenger = new Messenger(service);

Message msg = Message.obtain(null, 1);

final ServiceConnection myConn = this;

Handler h = new Handler(mHandler.getLooper()) {

@Override

public void handleMessage(Message msg) {

synchronized (mScreenshotLock) {

if (mScreenshotConnection == myConn) {

mContext.unbindService(mScreenshotConnection);

mScreenshotConnection = null;

mHandler.removeCallbacks(mScreenshotTimeout);

}

}

}

};

msg.replyTo = new Messenger(h);

msg.arg1 = msg.arg2 = 0;

try {

messenger.send(msg);

} catch (RemoteException e) {

}

}

}

@Override

public void onServiceDisconnected(ComponentName name) {}

};

if (mContext.bindService(intent, conn, Context.BIND_AUTO_CREATE)) {

mScreenshotConnection = conn;

mHandler.postDelayed(mScreenshotTimeout, 10000);

}

}

}

至此，再次编译源码并烧录，截屏功能实现了，现在还存有的是图标的状态处理了，这部分就不说明了。

实现截屏功能时，4.0上既然已实现该功能，那么就直接找源码，确认哪儿有实现，直接拿过来使用，尽量拿来主义，但又不失学习性。