Android 开发获取用户权限

Android某些功能的使用需要获得权限，对于一些常用权限，可以再Androidmanifest.xml中添加。添加方式如下：

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

 对于某些权限，在其中添加之后也不能获取，需要主动询问用户。询问方法如下：

import android.Manifest;
import android.app.Activity;
import android.content.pm.PackageManager;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.os.Bundle;
import android.os.Handler;
import android.content.Intent;

import java.util.ArrayList;

public class StartActivity extends Activity implements ActivityCompat.OnRequestPermissionsResultCallback{

    private static final int WAITTIME = 500;
    private ArrayList<String> permission=new ArrayList<String>();
    private ArrayList<String> askPermissionList = new ArrayList<String>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_start);
        permission.add(Manifest.permission.READ_EXTERNAL_STORAGE);
        permission.add(Manifest.permission.READ_PHONE_STATE);
        checkPermission(permission,askPermissionList);
        if(askPermissionList.size() >0) {
            requestPermissions(askPermissionList,1);

        }else{
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    Intent intent = new Intent(StartActivity.this, MainActivity.class);
                    startActivity(intent);
                    finish();

                }
            }, WAITTIME);

        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if(verifyPermisson(grantResults)){
            new Handler().postDelayed(new Runnable() {

                @Override
                public void run() {

                    Intent intent = new Intent(StartActivity.this,
                            MainActivity.class);
                    startActivity(intent);

                    finish();

                }
            }, WAITTIME);
        }else {
            finish();
        }
    }

    /***
     * 请求权限的方法，requestPermissions() 传入一个Activity，一个需要的权限的数组，
     * 和一个整形的request code，与用户完成交互后，系统会回调该方法并返回对用的request code
     * @param needAskPermisson
     * @param requestCode
     */
    private void requestPermissions(ArrayList<String> needAskPermisson,int requestCode) {
        String[] needpermisson = new String[needAskPermisson.size()];
        needpermisson = needAskPermisson.toArray(needpermisson);
        ActivityCompat.requestPermissions(this,needpermisson,1);//弹出对话框

    }


    /****
     * 判断应用权限的有无，如果没有这项权限，则将权限加入到askPermissionsList
     * @param permissions
     * @param askpermissionsList
     */
    private void checkPermission(ArrayList<String> permissions, ArrayList<String> askpermissionsList) {
        for(int i=0;i<permissions.size();i++) {
            //检查权限的方法，第一个参数是context，第二个参数是权限名，返回值为PERMISSION_GRANTED（有权限）和PERMISSION_DENIED(无权限）
            if(ContextCompat.checkSelfPermission(StartActivity.this,permissions.get(i))!= PackageManager.PERMISSION_GRANTED){
                askpermissionsList.add(permissions.get(i));
            }
        }

    }

    private  boolean verifyPermisson(int[] grantResults) {
        if(grantResults.length<1) {
            return false;
        }
        for(int result:grantResults) {
            if(result!=PackageManager.PERMISSION_GRANTED){
                return false;
            }
        }
        return true;
    }
}

一般情况下，在刚进入到应用时询问用户权限，在此处，StartActivity是程序的入口，在Androidmanifest.xml中进行定义，如下：

 <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".StartActivity"
            android:label="@string/title_activity_main"
            android:screenOrientation="portrait"
            android:theme="@style/AppTheme">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
</application>