Android 开发常用代码片段

1、图片旋转

Bitmap bitmapOrg = BitmapFactory.decodeResource(this.getContext().getResources(), R.drawable.moon);
Matrix matrix = new Matrix();
matrix.postRotate(-90);//旋转的角度
 
Bitmap resizedBitmap = Bitmap.createBitmap(bitmapOrg, 0, 0,
                    bitmapOrg.getWidth(), bitmapOrg.getHeight(), matrix, true);
BitmapDrawable bmd = new BitmapDrawable(resizedBitmap);

2、获取手机号码

//创建电话管理与手机建立连接
TelephonyManager tm = (TelephonyManager)activity.getSystemService(Context.TELEPHONY_SERVICE);

//获取手机号码
String phoneId = tm.getLine1Number();
//记得在manifest file中添加
    <uses-permission
android:name="android.permission.READ_PHONE_STATE" />

//程序在模拟器上无法实现，必须连接手机

3.格式化string.xml 中的字符串

// in strings.xml..
<string name="my_text">Thanks for visiting %s. You age is %d!</string>    
     
// and in the java code:
String.format(getString(R.string.my_text), "oschina", 33);

4、android设置全屏的方法

A.在java代码中设置

/** 全屏设置，隐藏窗口所有装饰 */
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);

B、在AndroidManifest.xml中配置

<activity android:name=".Login.NetEdit"  android:label="@string/label_net_Edit" 
		          android:screenOrientation="portrait" android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen">
	<intent-filter>
		<action android:name="android.intent.Net_Edit" />
		<category android:name="android.intent.category.DEFAULT" />
	</intent-filter>
</activity>

5、设置Activity为Dialog的形式

在AndroidManifest.xml中配置Activity节点是配置theme如下：

android:theme="@android:style/Theme.Dialog"

6、检查当前网络是否连上

ConnectivityManager con=(ConnectivityManager)getSystemService(Activity.CONNECTIVITY_SERVICE);  
boolean wifi=con.getNetworkInfo(ConnectivityManager.TYPE_WIFI).isConnectedOrConnecting();  
boolean internet=con.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).isConnectedOrConnecting(); 
//在AndroidManifest.xml 增加权限：
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

7、检测某个Intent是否有效

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

8、android 拨打电话

try {
   Intent intent = new Intent(Intent.ACTION_CALL);
   intent.setData(Uri.parse("tel:+110"));
   startActivity(intent);
} catch (Exception e) {
   Log.e("SampleApp", "Failed to invoke call", e);
}

9、android中发送Email

Intent i = new Intent(Intent.ACTION_SEND);  
//i.setType("text/plain"); //模拟器请使用这行
i.setType("message/rfc822") ; // 真机上使用这行
i.putExtra(Intent.EXTRA_EMAIL, new String[]{"[e-mail]","[e-mail]});  
i.putExtra(Intent.EXTRA_SUBJECT,"subject goes here");  
i.putExtra(Intent.EXTRA_TEXT,"body goes here");  
startActivity(Intent.createChooser(i, "Select email application."));

10、android中打开浏览器

Intent viewIntent = new    Intent("android.intent.action.VIEW",Uri.parse("http://vaiyanzi.cnblogs.com"));
startActivity(viewIntent);

11、android 获取设备唯一标识码

String android_id = Secure.getString(getContext().getContentResolver(), Secure.ANDROID_ID);

12、android中获取IP地址

public String getLocalIpAddress() {
    try {
        for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); 
		en.hasMoreElements();) {
            NetworkInterface intf = en.nextElement();
            for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); 
		enumIpAddr.hasMoreElements();) {
                InetAddress inetAddress = enumIpAddr.nextElement();
                if (!inetAddress.isLoopbackAddress()) {
                    return inetAddress.getHostAddress().toString();
                }
            }
        }
    } catch (SocketException ex) {
        Log.e(LOG_TAG, ex.toString());
    }
    return null;
}

13、android获取存储卡路径以及使用情况

/** 获取存储卡路径 */ 
File sdcardDir=Environment.getExternalStorageDirectory(); 
/** StatFs 看文件系统空间使用情况 */ 
StatFs statFs=new StatFs(sdcardDir.getPath()); 
/** Block 的 size*/ 
Long blockSize=statFs.getBlockSize(); 
/** 总 Block 数量 */ 
Long totalBlocks=statFs.getBlockCount(); 
/** 已使用的 Block 数量 */ 
Long availableBlocks=statFs.getAvailableBlocks(); 

14 android中添加新的联系人

private Uri insertContact(Context context, String name, String phone) {
	   
       ContentValues values = new ContentValues();
       values.put(People.NAME, name);
       Uri uri = getContentResolver().insert(People.CONTENT_URI, values);
       Uri numberUri = Uri.withAppendedPath(uri, People.Phones.CONTENT_DIRECTORY);
       values.clear();
       
       values.put(Contacts.Phones.TYPE, People.Phones.TYPE_MOBILE);
       values.put(People.NUMBER, phone);
       getContentResolver().insert(numberUri, values);
       
       return uri;
}

15、查看电池使用情况

Intent intentBatteryUsage = new Intent(Intent.ACTION_POWER_USAGE_SUMMARY);        
startActivity(intentBatteryUsage);

16、获取进程号

ActivityManager mActivityManager = (ActivityManager) this.getSystemService(ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> mRunningProcess = mActivityManager.getRunningAppProcesses(); int i = 1; for (ActivityManager.RunningAppProcessInfo amProcess : mRunningProcess) { Log.e("homer Application", (i++) + "  PID = " + amProcess.pid + "; processName = " + amProcess.processName); }	

17.设置背景图片和壁纸

//给ImageView设置图片，从存储卡中获取图片为Drawable,然后把Drawable设置为ImageView的背景

iv.setBackgroundDrawable(Drawable.createFromPath("/sdcard/a.jpg"));

//Activity的父类ContextWrapper方法setWallpaper，需要相应权限
setWallpaper(BitmapFactory.decodeFile("/sdcard/a.jpg"));

<uses-permission android:name="android.permission.SET_WALLPAPER" />

                            

参考推荐：

Android 获取屏幕尺寸与密度

Android 根据屏幕大小设置字体

Android Activity 全屏、横竖屏设置

Android模拟器无法上网问题