Android 动态权限申请

package com.dragon.android.permissionrequest;import android.Manifest;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.widget.Toast;public class MainActivity extends AppCompatActivity {    // 要申请的权限
    private String[] permissions = {Manifest.permission.WRITE_EXTERNAL_STORAGE};
    private AlertDialog dialog;    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);        // 版本判断。当手机系统大于 23 时，才有必要去判断权限是否获取
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {            // 检查该权限是否已经获取
            int i = ContextCompat.checkSelfPermission(this, permissions[0]);
            // 权限是否已经 授权 GRANTED---授权  DINIED---拒绝
            if (i != PackageManager.PERMISSION_GRANTED) {
                // 如果没有授予该权限，就去提示用户请求
                showDialogTipUserRequestPermission();
            }
        }
    }    // 提示用户该请求权限的弹出框
    private void showDialogTipUserRequestPermission() {        new AlertDialog.Builder(this)
                .setTitle("存储权限不可用")
                .setMessage("由于支付宝需要获取存储空间，为你存储个人信息；\n否则，您将无法正常使用支付宝")
                .setPositiveButton("立即开启", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        startRequestPermission();
                    }
                })
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        finish();
                    }
                }).setCancelable(false).show();
    }    // 开始提交请求权限
    private void startRequestPermission() {
        ActivityCompat.requestPermissions(this, permissions, 321);
    }    // 用户权限 申请 的回调方法
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);        if (requestCode == 321) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                if (grantResults[0] != PackageManager.PERMISSION_GRANTED) {
                    // 判断用户是否 点击了不再提醒。(检测该权限是否还可以申请)
                    boolean b = shouldShowRequestPermissionRationale(permissions[0]);
                    if (!b) {
                        // 用户还是想用我的 APP 的
                        // 提示用户去应用设置界面手动开启权限
                        showDialogTipUserGoToAppSettting();
                    } else
                        finish();
                } else {
                    Toast.makeText(this, "权限获取成功", Toast.LENGTH_SHORT).show();
                }
            }
        }
    }    // 提示用户去应用设置界面手动开启权限    private void showDialogTipUserGoToAppSettting() {        dialog = new AlertDialog.Builder(this)
                .setTitle("存储权限不可用")
                .setMessage("请在-应用设置-权限-中，允许支付宝使用存储权限来保存用户数据")
                .setPositiveButton("立即开启", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // 跳转到应用设置界面
                        goToAppSetting();
                    }
                })
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        finish();
                    }
                }).setCancelable(false).show();
    }    // 跳转到当前应用的设置界面
    private void goToAppSetting() {
        Intent intent = new Intent();        intent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
        Uri uri = Uri.fromParts("package", getPackageName(), null);
        intent.setData(uri);        startActivityForResult(intent, 123);
    }    //
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 123) {            if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                // 检查该权限是否已经获取
                int i = ContextCompat.checkSelfPermission(this, permissions[0]);
                // 权限是否已经 授权 GRANTED---授权  DINIED---拒绝
                if (i != PackageManager.PERMISSION_GRANTED) {
                    // 提示用户应该去应用设置界面手动开启权限
                    showDialogTipUserGoToAppSettting();
                } else {
                    if (dialog != null && dialog.isShowing()) {
                        dialog.dismiss();
                    }
                    Toast.makeText(this, "权限获取成功", Toast.LENGTH_SHORT).show();
                }
            }
        }
    }
}

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