android开发——动态申请权限

1、为什么需要动态申请权限？

因为google觉得有些权限是危险的，所以决定在android6.0（android 23）之后，程序在使用这些危险权限的时候，都需要询问用户是否可以使用这些权限。

2、危险的权限主要有哪些？

  和联系人、电话、短信、读写外部存储、相机、位置信息、传感器和日历有关的都涉及危险权限！下面举例5个：

    <!--以下是危险权限，需要动态申请-->
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.RECORD_AUDIO"/>
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

 3、如何动态申请？

 需要动态申请的危险权限都是需要在AndroidMenifest.xml中进行相应的配置，然后在加上下面的代码即可：

private int times = 0;
private final int REQUEST_PERMISSION  = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView();
        checkPermission();
}

private void checkPermission() {
        times++;
        final List<String> permissionsList = new ArrayList<>();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if ((checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED))
                permissionsList.add(Manifest.permission.CAMERA);
            if ((checkSelfPermission(Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED))
                permissionsList.add(Manifest.permission.RECORD_AUDIO);
            if ((checkSelfPermission(Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED)) {
                permissionsList.add(Manifest.permission.READ_PHONE_STATE);
            }
            if ((checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED)) {
                permissionsList.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);
            }
            if ((checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED)) {
                permissionsList.add(Manifest.permission.READ_EXTERNAL_STORAGE);
            }
            if (permissionsList.size() != 0) {
                if (times == 1) {
                    requestPermissions(permissionsList.toArray(new String[permissionsList.size()]),
                            REQUEST_PERMISSION);
                } else {
                    new AlertDialog.Builder(this)
                            .setCancelable(true)
                            .setTitle("提示")
                            .setMessage("获取不到授权，APP将无法正常使用，请允许APP获取权限！")
                            .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                                @Override
                                public void onClick(DialogInterface arg0, int arg1) {
                                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                                        requestPermissions(permissionsList.toArray(new String[permissionsList.size()]),
                                                REQUEST_PERMISSION);
                                    }
                                }
                            }).setNegativeButton("取消", new DialogInterface.OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface arg0, int arg1) {
                                        finish();
                                    }
                    }).show();
                }
            }
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        checkPermission();
    }