Android and android Official Website

Android and android Official Website

Sometimes you want to know whether an APP has registered a clear intent. For example, you want to check whether a receiver exists, then, enable some functions in your AP based on whether the hacker exists. We can check PackageManager.

Code

public boolean isIntentAvailable(Context context, String action) {      final PackageManager packageManager = context.getPackageManager();      final Intent intent = new Intent(action);      List<ResolveInfo> resolveInfo = packageManager.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);     if (resolveInfo.size() > 0) {          return true;      }     return false;  }

Dry Goods

Generally, the intent-filter must be set for the launcher activity in the manifest of the APP:

<intent-filter>                  <action android:name="android.intent.action.MAIN" />                  <category android:name="android.intent.category.LAUNCHER" />  </intent-filter>

You can use queryIntentActivities to obtain the launcher:

private void loadApps() {                   Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);                   mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);                     mApps = getPackageManager().queryIntentActivities(mainIntent, 0);           }

We can use a gridview in our app to show which apps are on the current mobile phone:

import java.util.List;       import android.app.Activity;   import android.content.Intent;   import android.content.pm.ResolveInfo;   import android.os.Bundle;   import android.view.View;   import android.view.ViewGroup;   import android.widget.BaseAdapter;   import android.widget.GridView;   import android.widget.ImageView;       public class MyHome extends Activity   {             GridView mGrid;                      @Override       public void onCreate(Bundle savedInstanceState) {                   super.onCreate(savedInstanceState);                             loadApps();                   setContentView(R.layout.main);                   mGrid = (GridView) findViewById(R.id.apps_list);                   mGrid.setAdapter(new AppsAdapter());           }                       private List<ResolveInfo> mApps;               private void loadApps() {                   Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);                   mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);                      mApps = getPackageManager().queryIntentActivities(mainIntent, 0);          }               public class AppsAdapter extends BaseAdapter       {                   public AppsAdapter() {         }                       public View getView(int position, View convertView, ViewGroup parent) {                           ImageView i;                               if (convertView == null) {                                   i = new ImageView(MyHome.this);                                   i.setScaleType(ImageView.ScaleType.FIT_CENTER);                                   i.setLayoutParams(new GridView.LayoutParams(50, 50));                           } else {                                   i = (ImageView) convertView;                           }                               ResolveInfo info = mApps.get(position);                          i.setImageDrawable(info.activityInfo.loadIcon(getPackageManager()));                               return i;                   }                           public final int getCount() {                          return mApps.size();                   }                       public final Object getItem(int position) {                           return mApps.get(position);                   }                       public final long getItemId(int position) {                           return position;                   }           }   }

You can click the listener to enable the app:

@Override 

Public void onItemClick (AdapterView <?> Parent, View view, int position, long id) {ResolveInfo info = mApps. get (position); // The package name of the application String pkg = info. activityInfo. packageName; // main activity class of the application String cls = info. activityInfo. name; ComponentName componet = new ComponentName (pkg, cls); Intent I = new Intent (); I. setComponent (componet); startActivity (I );}

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