Android权限申请库——EasyPermissions使用详解和打开相册方法

1、添加依赖

dependencies {
    implementation 'pub.devrel:easypermissions:3.0.0'
}

2、在AndroidManifest文件中添加需要的权限

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

3、复写onRequestPermissionsResult方法

@Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
 
        // 将返回结果转给EasyPermissions
        EasyPermissions.onRequestPermissionsResult(requestCode, permissions, grantResults, this);
    }

4、检查权限

String[] perms = {Manifest.permission.READ_EXTERNAL_STORAGE};
        if (EasyPermissions.hasPermissions(this, perms)) {
            // 已获取权限
            // ...
 
        } else {
            // 没有权限，现在去获取
            // ...
        }

5、申请权限

public static final int RC_READ_EXTERNAL_STORAGE = 1; // requestCode
EasyPermissions.requestPermissions(this, "申请内存权限",
                    RC_READ_EXTERNAL_STORAGE, perms);

6、实现EasyPermissions.PermissionCallbacks接口，处理申请结果

@Override
    public void onPermissionsGranted(int requestCode, @NonNull List<String> perms) {
        // 一些权限被授予
        Toast.makeText(this, "允许", Toast.LENGTH_SHORT).show();
    }
 
    @Override
    public void onPermissionsDenied(int requestCode, @NonNull List<String> perms) {
        // 一些权限被禁止
        Toast.makeText(this, "禁止", Toast.LENGTH_SHORT).show();
    }
}

7、如果用户点击了拒绝，并勾选了不再询问

@Override
public void onPermissionsDenied(int requestCode, List<String> perms) {
 
if (EasyPermissions.somePermissionPermanentlyDenied(this, perms)) {
    new AppSettingsDialog.Builder(this).build().show();
    //弹出个对话框 可以自定义
}

8、完整的Activity活动如下文章来源地址https://uudwc.com/A/Rqg0k

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.Manifest;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.WindowManager;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;

import net.sourceforge.pinyin4j.PinyinHelper;

import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.List;
import java.util.PrimitiveIterator;

import pub.devrel.easypermissions.AppSettingsDialog;
import pub.devrel.easypermissions.EasyPermissions;

public class MainActivity2 extends AppCompatActivity implements EasyPermissions.PermissionCallbacks{
    private TextView ta;
    private ImageView ig;
    int REQUEST_IMAGE_OPEN = 2;

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        // 将返回结果转给EasyPermissions
        EasyPermissions.onRequestPermissionsResult(requestCode, permissions, grantResults, this);
    }

    @Override
    public void onPermissionsGranted(int requestCode, @NonNull List<String> perms) {
        // 一些权限被授予
        Toast.makeText(this, "允许", Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onPermissionsDenied(int requestCode, @NonNull List<String> perms) {
        // 一些权限被禁止
        Toast.makeText(this, "禁止", Toast.LENGTH_SHORT).show();
        if (EasyPermissions.somePermissionPermanentlyDenied(this, perms)) {
            new AppSettingsDialog.Builder(this).build().show();
            //弹出个对话框 可以自定义
        }
    }

    public static final int RC_READ_EXTERNAL_STORAGE = 1; // requestCode
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        ta = (TextView) findViewById(R.id.ta);
        ig = (ImageView) findViewById(R.id.ig);
        String[] perms = {Manifest.permission.READ_EXTERNAL_STORAGE};
        if (EasyPermissions.hasPermissions(this, perms)) {
            // 已获取权限
            // ...
            Toast.makeText(this, "已获取权限", Toast.LENGTH_SHORT).show();
        } else {
            // 没有权限，现在去获取
            // ...
            Toast.makeText(this, " 没有权限，现在去获取", Toast.LENGTH_SHORT).show();

            EasyPermissions.requestPermissions(this, "申请内存权限",
                    RC_READ_EXTERNAL_STORAGE, perms);
        }

        ta.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //打开相册
                Intent intent = new  Intent(Intent.ACTION_PICK);
                //指定获取的是图片
                intent.setType("image/*");
                startActivityForResult(intent, REQUEST_IMAGE_OPEN);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        //将选择的图片显示
        if(requestCode == REQUEST_IMAGE_OPEN && resultCode == Activity.RESULT_OK &&data !=null){
            Uri uris;
            uris = data.getData();
            Bitmap bitmap = null;
            //Uri转化为Bitmap
            try {
                bitmap = getBitmapFromUri(uris);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
            ig.setImageBitmap(bitmap);
        }
    }
    //Uri转化为Bitmap
    private Bitmap getBitmapFromUri(Uri uri) throws FileNotFoundException {
        Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri));
        return bitmap;
    }

}