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. 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);

3. 设置全屏的方法

(1) 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);

(2) 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>

4. 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"

5. 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" />

6. 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;
}

7. 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);
}

8. 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[]{"test@gmail.com","test@163.com});
i.putExtra(Intent.EXTRA_SUBJECT,"subject goes here");
i.putExtra(Intent.EXTRA_TEXT,"body goes here");
startActivity(Intent.createChooser(i, "Select email application."));

9. android中打开浏览器

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

10. android 获取设备唯一标识码

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

11. 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;
}