手把手教你开发安卓Launcher.doc

launcher，也就是android的桌面应用程序。下图是android2.3的launcher应用程序：接下来我们要开发一个自己的launcher，使其替代系统的默认launcher。怎样使我们的应用程序成为一个launcher？下面我们就新建一个叫做MyHome的工程，具体步骤略。创建完工程后整个目录结构如下图：现在我们的AndroidManifest.xml文件这样的：请注意里面的内容。下面我们在其中添加上以下两行:?12此时AndroidManifest.xml文件是这样：?1234567891011121314151617181920此时运行程序，我们看不到任何特别之处。当按下home键时（模拟器上按下home会调出桌面应用），程序如图：我们看到了，我们开发的Myhome跟Launcher出现在了一起。重启模拟器，我们看到我们自己的程序已经可以作为home来运行了。ok。 第一步完成了：把我们的应用程序作为home。总结一下：要把我们的应用程序作为home，只需要在AndroidManifest.xml中添加：android手把手教你开发launcher （二）第二课：列出安装的应用程序预备知识： GridView的使用 改写BaseAdapter列出已经安装的应用程序是作为launcher必不可少的功能。下面我们就讲解怎样将应用程序列出来。程序运行后的样子如下：一. 修改main.xml，在其中添加一个GridView用来显示应用程序列表。修改后如下：?123456789101112二 . 通过PackageManager的api 查询已经安装的apk我们写一个叫做loadApps的方法将活得的应用程序列表放到private List mApps; 中，如下：?123456private void loadApps() Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);mApps = getPackageManager().queryIntentActivities(mainIntent, 0);三. 实现用于显示Gridview的Adapter，使其显示获得的应用程序列表直接上代码：?123456789101112131415161718192021222324252627282930313233343536373839404142public 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;最后整个Activity的代码如下?123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687package org.bangchui.myhome;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;/* Called when the activity is first created. */Overridepublic 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 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.setImageDrawa ble(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;第三课 启动安装的应用程序1. 监听GridView的onItemClick事件设置一个监听器是为了当gridView的某项被点击时，会有一个回调函数通知我们。我们调用mGrid.setOnItemClickListener(listener); 设置一个监听器mGrid.setOnItemClickListener(listener)中的listener是一个接口，其类型为：android.widget.AdapterView.OnItemClickListener，如下图所示：下面我们new一个android.widget.AdapterView.OnItemClickListener类型的对象作为参数。我们直接使用eclipde的自动补全功能来完成OnItemClickListener 的定义：?12345private OnItemClickListener listener = new OnItemClickListener() Overridepublic void onItemClick(AdapterView parent, View view, int position,long id) ;接口OnItemClickListener 中有一个方法叫做onItemClick，我们实现它即可。下面我对onItemClick的几个参数略作说明：parent 略view被点击的viewposition 被点击项的位置id 被点击项的id2.启动被点击应用的activity一般来讲，我们根据position即可知道被点击的项目是哪一项了。现在我们根据被点击的项目，取出对应的应用程序数据（主要是其中的主activity），然后启动activity。用下面代码实现：?123456789101112131415Overridepublic 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.activityI;ComponentName componet = new ComponentName(pkg, cls);Intent i = new Intent();i.setComponent(componet);startActivity(i);例如，我们点击计算器时，启动了计算器，如下图：现在整个类代码如下：复制代码1. package org.bangchui.myhome;2.3. import java.util.List;4.5. import android.app.Activity;6. import android.content.ComponentName;7. import android.content.Intent;8. import android.content.pm.ResolveInfo;9. import android.os.Bundle;10. import android.view.View;11. import android.view.ViewGroup;12. import android.widget.AdapterView;13. import android.widget.BaseAdapter;14. import android.widget.GridView;15. import android.widget.ImageView;16. import android.widget.AdapterView.OnItemClickListener;17.18. public class MyHome extends Activity 19. private List mApps;20. GridView mGrid;21. private OnItemClickListener listener = new OnItemClickListener() 22. Override23. public void onItemClick(AdapterView parent, View view, int position,long id) 24. ResolveInfo info = mApps.get(position);25. 26. /该应用的包名27. String pkg = info.activityInfo.packageName;28. /应用的主activity类29. String cls = info.activityI;30. 31. ComponentName componet = new ComponentName(pkg, cls);32. 33. Intent i = new Intent();34. i.setComponent(componet);35. startActivity(i);36. 37.38. ;39.40. /* Called when the activity is first created. */41. Override42. public void onCreate(Bundle savedInstanceState) 43. super.onCreate(savedInstanceState);44.45. loadApps();46. setContentView(R.layout.main);47. mGrid = (GridView) findViewById(R.id.apps_list);48. mGrid.setAdapter(new AppsAdapter();49.50. mGrid.setOnItemClickListener(listener);51. 52.53.54. private void loadApps() 55. Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);56. mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);57.58. mApps = getPackageManager().queryIntentActivities(mainIntent, 0);59. 60.61. public class AppsAdapter extends BaseAdapter 62. public AppsAdapter() 63. 64.65. public View getView(int position, View convertView, ViewGroup parent) 66. ImageView i;67.68. if (convertView = null) 69. i = new ImageView(MyHome.this);70. i.setScaleType(ImageView.ScaleType.FIT_CENTER);71. i.setLayoutParams(new GridView.LayoutParams(50, 50);72. else 73. i = (ImageView) convertView;74. 75.76. ResolveInfo info = mApps.get(position);77. i.setImageDrawable(info.activityInfo.loadIcon(getPackageManager();78.79. return i;80. 81.82. public final int getCount() 83. return mApps.size();84. 85.86. public final Object getItem(int position) 87. return mApps.get(position);88. 89.90. public final long getItemId(int position) 91. return position;92. 93. 94. 我们在前面的课程中已经列出了安装的应用程序，并且点击后可以启动应用程序了!下面我们来研究如何显示widget。源代码：附件出售：TestWidget.7z我们要达到这样的效果：点击“add widget” 后弹出widget列表，之后选择一个widget后显示在界面上，如下：第四课：显示widget1. 获取widget信息获取widget其实非常简单，我们只需要发送一个请求到系统，系统就会打开widget的列表，然后我们选择一个即可。代码如下：?1234567void addWidget() int appWidgetId = mAppWidgetHost.allocateAppWidgetId();Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK);pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);/ start the pick activitystartActivityForResult(pickIntent, bREQUEST_PICK_APPWIDGET/b);2. 添加widget的view到layout中当选择一个widget后会通过onActivityResult 通知到activity，widget的信息被包含在 Intent data中，详情看代码注释?1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) / The pattern used here is that a user PICKs a specific application,/ which, depending on the target, might need to CREATE the actual/ target./ For example, the user would PICK_SHORTCUT for Music playlist, and/ we/ launch over to the Music app to actually CREATE_SHORTCUT.if (resultCode = RESULT_OK) switch (requestCode) case REQUEST_PICK_APPWIDGET:addAppWidget(data);break;case REQUEST_CREATE_APPWIDGET:completeAddAppWidget(data);break;void addAppWidget(Intent data) / TODO: catch bad widget exception when sentint appWidgetId = data.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,-1);AppWidgetProviderInfo appWidget = mAppWidgetManager.getAppWidgetInfo(appWidgetId);/widget 包含设置信息不为空，则启动widget的设置界面if (appWidget.configure != null) / Launch over to configure widget, if neededIntent intent = new Intent(AppWidgetManager.ACTION_APPWIDGET_CONFIGURE);intent.setComponent(appWidget.configure);intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);startActivityForResultSafely(intent, REQUEST_CREATE_APPWIDGET); else /widget 包含设置信息为空,直接添加widget到layout中/ Otherwise just add itonActivityResult(REQUEST_CREATE_APPWIDGET, Activity.RESULT_OK, data);void startActivityForResultSafely(Intent intent, int requestCode) try startActivityForResult(intent, requestCode); catch (ActivityNotFoundException e) Toast.makeText(this, activity_not_found, Toast.LENGTH_SHORT).show(); catch (SecurityException e) Toast.makeText(this, activity_not_found, Toast.LENGTH_SHORT).show();/* 添加widget信息到layout中 * param data 包含了widget的信息*/private void completeAddAppWidget(Intent data) Bundle extras = data.getExtras();int appWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, -1);Log.d(TAG, dumping extras content= + extras.toString();AppWidgetProviderInfo appWidgetInfo = mAppWidgetManager.getAppWidgetInfo(appWidgetId);/ Perform actual inflation becaus