原本想搞一个退出程序时，把前一个应用程序的ＶＩＥＷ或者截图抓过来为我用，以实现更复杂的动画效果，尝试了很多方法，但都有或多或少的缺陷，可惜最后失败了。不过也算有所得。写文以标记。
其实抓图在4.0以后的版本中，还是很容易实现的，因为系统有十分完美的自带的截图。只要有源码，可以修改系统，通过执行screencap 和screenshot命令可以实现。
public static boolean RootCommand(String command) //申请root权限
{
Process process = null;
DataOutputStream os = null;
try
{
process = Runtime.getRuntime().exec("su");
os = new DataOutputStream(process.getOutputStream());
os.writeBytes(command + "\n");
os.writeBytes("exit\n");
os.flush();
process.waitFor();
} catch (Exception e)
{
Log.d("*** DEBUG ***", "ROOT REE" + e.getMessage());
return false;
} finally
{
try
{
if (os != null)
{
os.close();
}
process.destroy();
} catch (Exception e)
{
}
}
Log.d("*** DEBUG ***", "Root SUC ");
return true;
}
通过调用系统的截屏程序也能实现。如果要实现进入自己的软件前获得屏幕ＢＵＦＦＥＲ，下面的函数可以实现，返回的ＢＩＴＭＡＰ就是前一屏的BITMAP,不过如果抓图是竖屏，进入自己的程序后变横屏，这个图就没办法变横了。因为我是需要在锁屏时，把前一屏数据结果锁屏做一个动画，所以如果解锁时，前一窗口数据已经变化，这个载屏就没什么用处了。无法实现解锁窗口与前一程序无缝衔接。同时如果你的锁屏如果是在黑屏后才进入，那么这个裁屏截到的也是黑屏了，大家都懂的。
public Bitmap getScreenBuffer()
{
Display mDisplay;
DisplayMetrics mDisplayMetrics;
Matrix mDisplayMatrix = new Matrix(); WindowManager mWindowManager = (WindowManager) mContext
.getSystemService(Context.WINDOW_SERVICE);
mDisplay = mWindowManager.getDefaultDisplay();
mDisplayMetrics = new DisplayMetrics();
mDisplay.getRealMetrics(mDisplayMetrics);
mDisplay.getRealMetrics(mDisplayMetrics);
float[] dims = { mDisplayMetrics.widthPixels,
mDisplayMetrics.heightPixels }; mlock = Surface.screenshot((int) dims[0], (int) dims[1]);
return mlock;
}
截屏函数在上锁时，由于会黑屏，结果只能抓到黑屏图，所以可以通过调用4.0以后最近运行的程序的快照来替代，大概是ActivityManager.java 中getTaskThumbnails(int)}.但由于我的需要支持横竖屏，所以当解锁前后横竖屏状态不同时，这个快照也失去了意义。
那么只剩下最后一种方式，获得上一次运行的activity的实例，进而获得其getDecorView，把其getDecorView转为BITMAP来运用。获得前一次运行的程序，可以通过以下代码获取：
ActivityManager am = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
List<RunningTaskInfo> cn = am.getRunningTasks(2);
RunningTaskInfo taskInfo = cn.get(1);
ComponentName name = taskInfo.topActivity;
Log.i("jia @@@@@@", "name.getClassName() = "+name.getClassName());
Log.i("jia @@@@@@", "name.getPackageName() = "+name.getPackageName());
Log.i("jia @@@@@@", "name.getClass() = "+name.getClass().toString());
Log.i("jia @@@@@@", "name.getShortClassName() = "+name.getShortClassName());
getRunningTasks可以获得当前运行的程序，参数2为获得最近两个程序，
cn.get(1);为获得倒数第二个运行的程序，如果参数为0，就是当前程序
然后使用动态加载反射其activity
Context cc = null;
try {
cc = this.createPackageContext(name.getPackageName(), Context.CONTEXT_INCLUDE_CODE | Context.CONTEXT_IGNORE_SECURITY);
} catch (NameNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//载入这个类
Class clazz = null;
try {
clazz = cc.getClassLoader().loadClass(name.getClassName());
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Activity aa = null;
try {
aa = (Activity)clazz.newInstance();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Intent in = new Intent(cc, clazz);
in.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS);
this.startActivity(in);
overridePendingTransition(android.R.anim.slide_in_left,
android.R.anim.slide_out_right);
最后，完整的代码
package com.example.testtaskactivity; import java.util.List; import android.os.Bundle;
import android.app.Activity;
import android.app.ActivityGroup;
import android.app.ActivityManager;
import android.app.ActivityManager.RunningTaskInfo;
import android.app.LocalActivityManager;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager.NameNotFoundException;
import android.graphics.Rect;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.Window;
import android.widget.RelativeLayout.LayoutParams; public class MainActivity extends ActivityGroup {
private LocalActivityManager localActivityManager = null; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
} @Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
} public void gettaskview(View view) {
ActivityManager am = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
List<RunningTaskInfo> cn = am.getRunningTasks(2);
RunningTaskInfo taskInfo = cn.get(1);
ComponentName name = taskInfo.topActivity;
Log.i("jia @@@@@@", "name.getClassName() = " + name.getClassName());
Log.i("jia @@@@@@", "name.getPackageName() = " + name.getPackageName());
Log.i("jia @@@@@@", "name.getClass() = " + name.getClass().toString());
Log.i("jia @@@@@@",
"name.getShortClassName() = " + name.getShortClassName());
Activity a = null;
Class c = null; /*
* try { c = Class.forName(name.getClassName()); Log.i("jia @@@@@@",
* "c = "+c.getName().toString()); } catch (ClassNotFoundException e) {
* // TODO Auto-generated catch block e.printStackTrace();
* Log.i("jia @@@@@@", "11111111111111111 "); } try { a =
* (Activity)c.newInstance(); Log.i("jia @@@@@@", "a = "+a.toString());
* } catch (InstantiationException e) { // TODO Auto-generated catch
* block e.printStackTrace(); } catch (IllegalAccessException e) { //
* TODO Auto-generated catch block e.printStackTrace(); }
*/
/*
* View currentScreen = a.getWindow().getDecorView();
*
* this.addContentView(currentScreen, new LayoutParams(
* LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
*/
// this.createPackageContext(packageName, flags);
Context cc = null;
try {
cc = this.createPackageContext(name.getPackageName(),
Context.CONTEXT_INCLUDE_CODE
| Context.CONTEXT_IGNORE_SECURITY);
} catch (NameNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// 载入这个类
Class clazz = null;
try {
clazz = cc.getClassLoader().loadClass(name.getClassName());
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Activity aa = null;
try {
aa = (Activity) clazz.newInstance();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// PolicyManager.makeNewWindow(context);
// View v = aa.getWindow().getDecorView();
// setContentView(v);
Intent in = new Intent(cc, clazz);
in.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
| Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS);
this.startActivity(in);
overridePendingTransition(android.R.anim.slide_in_left,
android.R.anim.slide_out_right);
/*
* Rect frame = new Rect();
* getWindow().getDecorView().getWindowVisibleDisplayFrame(frame); int
* statusBarHeight = frame.top; Log.i("jia @@@@@@",
* "statusBarHeight = " + statusBarHeight);
*
*
* LocalActivityManager mgr = this.getLocalActivityManager();
* Intent in
* = new Intent(this, clazz); in.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
* | Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS); Window w =
* mgr.startActivity("aaa", in); View v =w.getDecorView(); //View v =
* a.getWindow().getDecorView(); setContentView(v);
*/ } }
这样可以使唤得我们可以在不同的应用之间使用动画跳转，但我尝试使用Window w = mgr.startActivity("aaa", in)获得前一activity的VIEW时，提示该activity没有在我的
AndroidManifest.xml中声明，第三方的和系统的应用，本不该在我的应用中声明，可能是因为别人的VIEW不能为我所用吧。抓图程序需要system权限，需要在AndroidManifest.xml文件的manifest标签中声明，android:sharedUserId="android.uid.system"。要不抓不了图，也获取不了屏幕的bitmap，Surface.screenshot函数是系统的隐藏ＡＰＩ，不可在ＡＰＫ中直接使用，需要写一个如下的ＭＫ文件，放在源码目录下使用ＭＭ编绎：
LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE_TAGS := optional
LOCAL_JAVA_LIBRARIES := bouncycastle \
framework \
mediatek-framework
LOCAL_CERTIFICATE := platform
LOCAL_STATIC_JAVA_LIBRARIES := \
android-support-v4
LOCAL_SRC_FILES := $(call all-java-files-under, src)
LOCAL_PACKAGE_NAME := Scr
#LOCAL_SDK_VERSION := current
include $(BUILD_PACKAGE)
# Use the following include to make our test apk.
include $(call all-makefiles-under,$(LOCAL_PATH))
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