Android -- queryIntentActivities

某些时候你想要知道某个APP是否有注册了一个明确的intent，比如说你想要检查某个receiver是否存在，然后根据是否存在来这个receiver来在你的AP里面enable某些功能。我们可以通过PackageManager来check它。

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;

}

干货

一般APP的manifest里面要设置为launcher的activity总是要设置intent-filter：

<intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

</intent-filter>

可以通过queryIntentActivities来获得有哪些launcher：

private void loadApps() {

        Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);

        mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);

        mApps = getPackageManager().queryIntentActivities(mainIntent, 0);

    }

我们可以在自己的app上用一个gridview显示出当前手机有哪些app：

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;

        }

    }

}

可以设置点击监听器去开启app：

@Override

public void onItemClick(AdapterView<?> parent, View view, int position,long id) {

    ResolveInfo info = mApps.get(position);

    //该应用的包名

    String pkg = info.activityInfo.packageName;

    //应用的主activity类

    String cls = info.activityInfo.name;

    ComponentName componet = new ComponentName(pkg, cls);

    Intent i = new Intent();

    i.setComponent(componet);

    startActivity(i);

}

巴特西

Android -- queryIntentActivities

code

干货

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