Android Activity中启动另一应用程序的方法，无需得到类名

在网上搜索了一会相关的实现代码，发现所有的文章都说是需要包名和类名。但是人家的程序，我们怎么可能知道哪个是第一个启动的Activity？所以，真正用在项目上，那种方法基本上没什么用的。于是查看官方文档，发现这样一个方法：

public abstract Intent getLaunchIntentForPackage (String packageName)

英文原文：Return a “good” intent to launch a front-door activity in a package, for use for example to implement an “open” button when browsing through packages.大概意思就是返回一个程序入口的Intent,就是Java程序的Main方法。
这下简单了，直接startActivity(返回的intent)即可。

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
 
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.AdapterView.OnItemClickListener;
 
public class Main extends Activity {
	/** Called when the activity is first created. */
	ListView lv;
	Adapter adapter;
	ArrayList<HashMap<String, Object>> items = new ArrayList<HashMap<String, Object>>();
	PackageManager pm;
 
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		lv = (ListView) findViewById(R.id.lv);
		final PackageManager pm = getPackageManager();
		// 得到PackageManager对象
		List<PackageInfo> packs = pm
				.getInstalledPackages(PackageManager.GET_UNINSTALLED_PACKAGES);
		// 得到系统 安装的所有程序包的PackageInfo对象
 
		for (PackageInfo pi : packs) {
			HashMap<String, Object> map = new HashMap<String, Object>();
			map.put("icon", pi.applicationInfo.loadIcon(pm));
			// 图标
			map.put("appName", pi.applicationInfo.loadLabel(pm));
			// 应用名
			map.put("packageName", pi.packageName);
			// 包名
			items.add(map);
			// 循环读取存到HashMap,再增加到ArrayList.一个HashMap就是一项
		}
 
		adapter = new Adapter(this, items, R.layout.piitem, new String[] {
				"icon", "appName", "packageName" }, new int[] { R.id.icon,
				R.id.appName, R.id.packageName });
		// 参数:Context,ArrayList(item的集合),item的layout,包含ArrayList中Hashmap的key的数组,key所对应的值相对应的控件id
		lv.setAdapter(adapter);
		lv.setOnItemClickListener(new OnItemClickListener() {
 
			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				// TODO Auto-generated method stub
				String packageName = (String) items.get(position).get(
						"packageName");
				//取到点击的包名
				Intent i = pm.getLaunchIntentForPackage(packageName);
				//如果该程序不可启动（像系统自带的包，有很多是没有入口的）会返回NULL
				if (i != null)
					startActivity(i);
			}
 
		});
 
	}
 
}

评论

8 楼 小唄潴 2015-02-06  

不错，不需要知道启动类就可以启动另外一个apk

7 楼 flyingsir_zw 2014-09-05  

[code=]
import java.text.Collator;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.app.ListActivity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class ListSamples extends ListActivity {

	private static final String TAG = "ListSamples";
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Intent intent = getIntent();
        String path = intent.getStringExtra("com.jakewharton.android.viewpagerindicator.sample.Path");

        if (path == null) {
            path = "";
        }

        setListAdapter(new SimpleAdapter(this, getData(path),
                android.R.layout.simple_list_item_1, new String[] { "title" },
                new int[] { android.R.id.text1 }));
        getListView().setTextFilterEnabled(true);
    }

    protected List<Map<String, Object>> getData(String prefix) {
        List<Map<String, Object>> myData = new ArrayList<Map<String, Object>>();

        Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
        mainIntent.addCategory("com.jakewharton.android.viewpagerindicator.sample.SAMPLE");

        PackageManager pm = getPackageManager();
        List<ResolveInfo> list = pm.queryIntentActivities(mainIntent, 0);

        if (null == list)
            return myData;

        String[] prefixPath;
        String prefixWithSlash = prefix;

        if (prefix.equals("")) {
            prefixPath = null;
        } else {
            prefixPath = prefix.split("/");
            prefixWithSlash = prefix + "/";
        }

        int len = list.size();

        Map<String, Boolean> entries = new HashMap<String, Boolean>();

        for (int i = 0; i < len; i++) {
            ResolveInfo info = list.get(i);
            CharSequence labelSeq = info.loadLabel(pm);
            String label = labelSeq != null
                    ? labelSeq.toString()
                    : info.activityInfo.name;

            if (prefixWithSlash.length() == 0 || label.startsWith(prefixWithSlash)) {

                String[] labelPath = label.split("/");

                String nextLabel = prefixPath == null ? labelPath[0] : labelPath[prefixPath.length];

                if ((prefixPath != null ? prefixPath.length : 0) == labelPath.length - 1) {
                    addItem(myData, nextLabel, activityIntent(
                            info.activityInfo.applicationInfo.packageName,
                            info.activityInfo.name));
                } else {
                    if (entries.get(nextLabel) == null) {
                        addItem(myData, nextLabel, browseIntent(prefix.equals("") ? nextLabel : prefix + "/" + nextLabel));
                        entries.put(nextLabel, true);
                    }
                }
            }
        }

        Collections.sort(myData, NAME_COMPARATOR);

        return myData;
    }

    private final static Comparator<Map<String, Object>> NAME_COMPARATOR =
        new Comparator<Map<String, Object>>() {
        private final Collator   collator = Collator.getInstance();

        public int compare(Map<String, Object> map1, Map<String, Object> map2) {
            return collator.compare(map1.get("title"), map2.get("title"));
        }
    };

    protected Intent activityIntent(String pkg, String componentName) {
        Intent result = new Intent();
        result.setClassName(pkg, componentName);
        return result;
    }

    protected Intent browseIntent(String path) {
        Intent result = new Intent();
        result.setClass(this, ListSamples.class);
        result.putExtra("com.jakewharton.android.viewpagerindicator.sample.Path", path);
        return result;
    }

    protected void addItem(List<Map<String, Object>> data, String name, Intent intent) {
        Map<String, Object> temp = new HashMap<String, Object>();
        temp.put("title", name);
        temp.put("intent", intent);
        data.add(temp);
    }

    @Override
    @SuppressWarnings("unchecked")
    protected void onListItemClick(ListView l, View v, int position, long id) {
        Map<String, Object> map = (Map<String, Object>)l.getItemAtPosition(position);
        
        Log.e(TAG, "intent title = "+ map.get("title"));
        Intent intent = (Intent) map.get("intent");
        startActivity(intent);
    }
}

6 楼 kyson 2014-03-20  

特地登录了来感谢博主！！！

5 楼 linnanbin2012 2013-09-26  

不能用啊！

4 楼 c2unix 2012-07-20  

楼主这篇帖子帮了我巨大的忙，谢谢！！！   

3 楼 gundumw100 2011-08-04  

jm417113220 写道

一般第一个启动的Activty 会在项目的AndroidManifest.xml 文件里面有写到的

那问题搞定了哇？

2 楼 gundumw100 2011-08-04  

那问题搞定了哇？

1 楼 jm417113220 2011-08-04  

一般第一个启动的Activty 会在项目的AndroidManifest.xml 文件里面有写到的