之前一篇博客初试了Android6.0系统的动态权限申请，成功之后开始思考将权限申请功能封装以供更加方便的调用。

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查阅6.0系统权限相关的API，整个权限申请需要调用三个方法：

1. ContextCompat.checkSelfPermission() 

检查应用是否拥有该权限，被授权返回值为PERMISSION_GRANTED，否则返回PERMISSION_DENIED

 /*** Determine whether <em>you</em> have been granted a particular permission.** @param permission The name of the permission being checked.** @return {@link android.content.pm.PackageManager#PERMISSION_GRANTED} if you have the* permission, or {@link android.content.pm.PackageManager#PERMISSION_DENIED} if not.** @see android.content.pm.PackageManager#checkPermission(String, String)*/public static int checkSelfPermission(@NonNull Context context, @NonNull String permission) {if (permission == null) {throw new IllegalArgumentException("permission is null");}return context.checkPermission(permission, android.os.Process.myPid(), Process.myUid());}

2、ActivityCompat.requestPermissions()

/*** Requests permissions to be granted to this application. These permissions* must be requested in your manifest, they should not be granted to your app,* and they should have protection level {@link android.content.pm.PermissionInfo* #PROTECTION_DANGEROUS dangerous}, regardless whether they are declared by* the platform or a third-party app.* <p>* Normal permissions {@link android.content.pm.PermissionInfo#PROTECTION_NORMAL}* are granted at install time if requested in the manifest. Signature permissions* {@link android.content.pm.PermissionInfo#PROTECTION_SIGNATURE} are granted at* install time if requested in the manifest and the signature of your app matches* the signature of the app declaring the permissions.* </p>* <p>* If your app does not have the requested permissions the user will be presented* with UI for accepting them. After the user has accepted or rejected the* requested permissions you will receive a callback reporting whether the* permissions were granted or not. Your activity has to implement {@link* android.support.v4.app.ActivityCompat.OnRequestPermissionsResultCallback}* and the results of permission requests will be delivered to its {@link* android.support.v4.app.ActivityCompat.OnRequestPermissionsResultCallback#onRequestPermissionsResult(* int, String[], int[])} method.* </p>* <p>* Note that requesting a permission does not guarantee it will be granted and* your app should be able to run without having this permission.* </p>* <p>* This method may start an activity allowing the user to choose which permissions* to grant and which to reject. Hence, you should be prepared that your activity* may be paused and resumed. Further, granting some permissions may require* a restart of you application. In such a case, the system will recreate the* activity stack before delivering the result to your onRequestPermissionsResult(* int, String[], int[]).* </p>* <p>* When checking whether you have a permission you should use {@link* #checkSelfPermission(android.content.Context, String)}.* </p>** @param activity The target activity.* @param permissions The requested permissions.* @param requestCode Application specific request code to match with a result*    reported to {@link OnRequestPermissionsResultCallback#onRequestPermissionsResult(*    int, String[], int[])}.** @see #checkSelfPermission(android.content.Context, String)* @see #shouldShowRequestPermissionRationale(android.app.Activity, String)*/public static void requestPermissions(final @NonNull Activity activity,final @NonNull String[] permissions, final int requestCode) {if (Build.VERSION.SDK_INT >= 23) {ActivityCompatApi23.requestPermissions(activity, permissions, requestCode);} else if (activity instanceof OnRequestPermissionsResultCallback) {Handler handler = new Handler(Looper.getMainLooper());handler.post(new Runnable() {@Overridepublic void run() {final int[] grantResults = new int[permissions.length];PackageManager packageManager = activity.getPackageManager();String packageName = activity.getPackageName();final int permissionCount = permissions.length;for (int i = 0; i < permissionCount; i++) {grantResults[i] = packageManager.checkPermission(permissions[i], packageName);}((OnRequestPermissionsResultCallback) activity).onRequestPermissionsResult(requestCode, permissions, grantResults);}});}}

3、AppCompatActivity.onRequestPermissionsResult() 
该方法类似于Activity的OnActivityResult()的回调方法，主要接收请求授权的返回值

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下面开始在项目中进行权限封装： 
1、新建一个BaseActivity活动，extends自AppCompatActivity。这里将权限申请设计成基类，让项目中的所有活动都继承BaseActivity类。 
延伸学习：关于extends和implements的区别参考

2、声明两个Map类型的变量，用于存放取得权限后的运行和未获取权限时的运行。 
延伸学习：java中Map,List与Set的区别

 private Map<Integer, Runnable> allowablePermissionRunnables = new HashMap<>();private Map<Integer, Runnable> disallowblePermissionRunnables = new HashMap<>();

3、实现requesPermission方法。

* @param requestId            请求授权的Id，唯一即可* @param permission           请求的授权* @param allowableRunnable    同意授权后的操作* @param disallowableRunnable 禁止授权后的操作**/protected void requestPermission(int requestId, String permission,Runnable allowableRunnable, Runnable disallowableRunnable) {if (allowableRunnable == null) {throw new IllegalArgumentException("allowableRunnable == null");}allowablePermissionRunnables.put(requestId, allowableRunnable);if (disallowableRunnable != null) {disallowblePermissionRunnables.put(requestId, disallowableRunnable);}//版本判断if (Build.VERSION.SDK_INT >= 23) {//检查是否拥有权限int checkPermission = ContextCompat.checkSelfPermission(MyApplication.getContext(), permission);if (checkPermission != PackageManager.PERMISSION_GRANTED) {//弹出对话框请求授权ActivityCompat.requestPermissions(BaseActivity.this, new String[]{permission}, requestId);return;} else {allowableRunnable.run();}} else {allowableRunnable.run();}}

4、实现onRequestPermissionsResult方法。

 @Overridepublic void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {super.onRequestPermissionsResult(requestCode, permissions, grantResults);if (grantResults[0] == PackageManager.PERMISSION_GRANTED){Runnable allowRun=allowablePermissionRunnables.get(requestCode);allowRun.run();}else {Runnable disallowRun = disallowblePermissionRunnables.get(requestCode);disallowRun.run();}}

5、调用

public static final String CONTACT_PERMISSION = android.Manifest.permission.READ_CONTACTS;public static final int readContactRequest = 1;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.content_get_contacts);ContactsLv = (ListView) findViewById(R.id.ContactsLv);adapter = new ContactsAdapter(list, this);ContactsLv.setAdapter(adapter);requestPermission(readContactRequest, CONTACT_PERMISSION, new Runnable() {@Overridepublic void run() {getContacts();}}, new Runnable() {@Overridepublic void run() {getContactsDenied();}});}