android 嵌套 apk 从一个apk启动另外一个apk

a.apk-主应用  b.apk-被启动应用

主要思想：把b.apk放到assets目录下，由于有大小限制（1M），所以改名成b.mp3(因为mp3,jpg,png,mp4等不会检查，不会限制大小)，然后在用的时候再改回来

1.具体实现：

public void intallApp(Context context) {
try {
String path = context.getFilesDir().getAbsolutePath()+ "/b.apk";  //从assets中解压到这个目录

File f = new File(path);
if (!f.exists()) {
f.createNewFile();
}
InputStream is = context.getAssets().open("b.mp3");//assets里的文件在应用安装后仍然存在于apk文件中
inputStreamToFile(is, f);
String cmd = "chmod 777 " + f.getAbsolutePath();
Runtime.getRuntime().exec(cmd);
cmd = "chmod 777 " + f.getParent();
Runtime.getRuntime().exec(cmd);
// 尝试提升上2级的父文件夹权限，在阅读插件下载到手机存储时，刚好用到了2级目录
// /data/data/packagename/files/这个目录下面所有的层级目录都需要提升权限，才可安装apk，弹出安装界面
cmd = "chmod 777 " + new File(f.getParent()).getParent();
Runtime.getRuntime().exec(cmd);
Intent intent = new Intent();
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.setAction(android.content.Intent.ACTION_VIEW);

/* 调用getMIMEType()来取得MimeType */
String type = "application/vnd.android.package-archive";
/* 设置intent的file与MimeType */
intent.setDataAndType(Uri.fromFile(f), type);
context.startActivity(intent);
} catch (ActivityNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

public void inputStreamToFile(InputStream inputStream,File file){
///InputStream inputStream = null;
OutputStream outputStream = null;
try {
// read this file into InputStream
//inputStream = new FileInputStream("test.txt");
 
// write the inputStream to a FileOutputStream
outputStream = new FileOutputStream(file);
 
int read = 0;
byte[] bytes = new byte[1024];
 
while ((read = inputStream.read(bytes)) != -1) {
outputStream.write(bytes, 0, read);
}
 
System.out.println("Done!");
 
} catch (IOException e) {
e.printStackTrace();
} finally {
if (inputStream != null) {
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (outputStream != null) {
try {
// outputStream.flush();
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
 
}
}
}

2.如果是启动已安装的应用，实现如下：

public boolean startApp(Context context, String packageName) {
//String packageName = "XXX";
Intent intent = new Intent(Intent.ACTION_MAIN, null);
intent.addCategory(Intent.CATEGORY_LAUNCHER);
PackageManager pm = context.getPackageManager();
List<ResolveInfo> listInfos = pm.queryIntentActivities(intent, 0);
String className = null;
for (ResolveInfo info : listInfos) {
if (packageName.equals(info.activityInfo.packageName)) {
className = info.activityInfo.name;
break;
}
}
if (className != null && className.length() > 0) {
intent.setComponent(new ComponentName(packageName, className));
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
| Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);
context.startActivity(intent);
return true;
}
return false;
}

如果你知道包名,还知道作为启动的那activity的类名，就更简单了，就可以省掉上面查找的过程，直接启动。