應用場景
通過這個案例,我們可以瞭解一下動態代理技術,並且能夠在不改變版本號的情況下,動態修改版本號進行升級功能的測試,主要實現原理是通過動態代理getPackageInfo()來mock數據。
一、創建PackageManagerHook代理類
public class PackageManagerHook {
/**
* 越早hook越好,推薦在Application.attachBaseContext中調用
*/
public static void hook(final Context context) {
try {
//1、得到ActivityThread類
Class<?> activityThreadClz = Class.forName("android.app.ActivityThread");
Method currentActivityThread = activityThreadClz.getMethod("currentActivityThread");
//2、得到當前的ActivityThread對象
Object activityThread = currentActivityThread.invoke(null);
//3、得到PackageManager對象
Method getPackageManager = activityThreadClz.getMethod("getPackageManager");
final Object pkgManager = getPackageManager.invoke(activityThread);
Class<?> packageManagerClz = Class.forName("android.content.pm.IPackageManager");
//hook sPackageManager
Field packageManagerField = activityThreadClz.getDeclaredField("sPackageManager");
packageManagerField.setAccessible(true);
//動態代理
packageManagerField.set(activityThread, Proxy.newProxyInstance(context.getClassLoader(),
new Class[] { packageManagerClz }, new InvocationHandler() {
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
Object result = method.invoke(pkgManager,args);
if ("getPackageInfo".equals(method.getName())){
PackageInfo pkgInfo = (PackageInfo) result;
//修改App的版本信息
pkgInfo.versionCode = 520;
pkgInfo.versionName = "version:5.2.0";
}
return result;
}
}));
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
}
}
}
二、創建ProxyApplication
public class ProxyApplication extends Application {
@Override
protected void attachBaseContext(Context base) {
super.attachBaseContext(base);
PackageManagerHook.hook(this);
}
}
三、在AndroidManifest.xml設置
<application
android:name=".ProxyApplication"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
四、創建佈局文件
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:textColor="#222222"
android:textSize="18dp" />
</RelativeLayout>
五、在Activity中取值
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView textView = findViewById(R.id.text);
PackageManager manager = this.getPackageManager();
try {
PackageInfo info = manager.getPackageInfo(this.getPackageName(), 0);
textView.setText(info.versionName + "," + info.versionCode);
} catch (PackageManager.NameNotFoundException e) {
e.printStackTrace();
}
}
}
六、運行結果
小結
通過上述步驟,我們可以通過動態代理技術,修改App的版本號和版本名,重點理解一下PackageManagerHook中的代碼,祝大家學習愉快~