在Android开发中经常会遇到Android系统适配问题，出现这一问题是因为Android6.0以后对系统的一些权限进行了限制，而在开发中经常会用到这些权限，网上有 许多做法都是用到哪个权限就获取哪个权限，这样的做法会造成代码的紊乱，今天带来一种方法在获取到系统权限的同时又不会造成系统业务代码， 逻辑代码的紊乱。
创建一个类（判断是否缺少权限）：
public class PermissionsChecker {
private final Context mContext;
public PermissionsChecker(Context context) {
mContext = context.getApplicationContext();
}
// 判断权限集合
public boolean lacksPermissions(String... permissions) {
for (String permission : permissions) {
if (lacksPermission(permission)) {
return true;
}
}
return false;
}
// 判断是否缺少权限
private boolean lacksPermission(String permission) {
return ContextCompat.checkSelfPermission(mContext, permission) ==
PackageManager.PERMISSION_DENIED;
}
}
通过这个类的实例对象调用lacksPermissions()方法判断是否缺少所需权限。
然后创建一个Activity，通过这个Activity弹出系统增加的权限的弹窗以及界面：
public class PermissionsActivity extends AppCompatActivity {
public static final int PERMISSIONS_GRANTED = 0; // 权限授权
public static final int PERMISSIONS_DENIED = 1; // 权限拒绝
private static final int PERMISSION_REQUEST_CODE = 0; // 系统权限管理页面的参数
private static final String EXTRA_PERMISSIONS =
"me.chunyu.clwang.permission.extra_permission"; // 权限参数
private static final String PACKAGE_URL_SCHEME = "package:"; // 方案
private PermissionsChecker mChecker; // 权限检测器
private boolean isRequireCheck; // 是否需要系统权限检测
// 启动当前权限页面的公开接口
public static void startActivityForResult(Activity activity, int requestCode, String... permissions) {
Intent intent = new Intent(activity, PermissionsActivity.class);
intent.putExtra(EXTRA_PERMISSIONS, permissions);
ActivityCompat.startActivityForResult(activity, intent, requestCode, null);
}
@Override protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getIntent() == null || !getIntent().hasExtra(EXTRA_PERMISSIONS)) {
throw new RuntimeException("PermissionsActivity需要使用静态startActivityForResult方法启动!");
}
setContentView(R.layout.activity_permissions);
mChecker = new PermissionsChecker(this);
isRequireCheck = true;
}
@Override protected void onResume() {
super.onResume();
if (isRequireCheck) {
String[] permissions = getPermissions();
if (mChecker.lacksPermissions(permissions)) {
requestPermissions(permissions); // 请求权限
} else {
allPermissionsGranted(); // 全部权限都已获取
}
} else {
isRequireCheck = true;
}
}
// 返回传递的权限参数
private String[] getPermissions() {
return getIntent().getStringArrayExtra(EXTRA_PERMISSIONS);
}
// 请求权限兼容低版本
private void requestPermissions(String... permissions) {
ActivityCompat.requestPermissions(this, permissions, PERMISSION_REQUEST_CODE);
}
// 全部权限均已获取
private void allPermissionsGranted() {
setResult(PERMISSIONS_GRANTED);
finish();
}
/**
* 用户权限处理,
* 如果全部获取, 则直接过.
* 如果权限缺失, 则提示Dialog.
*
* @param requestCode 请求码
* @param permissions 权限
* @param grantResults 结果
*/
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if (requestCode == PERMISSION_REQUEST_CODE && hasAllPermissionsGranted(grantResults)) {
isRequireCheck = true;
allPermissionsGranted();
} else {
isRequireCheck = false;
showMissingPermissionDialog();
}
}
// 含有全部的权限
private boolean hasAllPermissionsGranted(@NonNull int[] grantResults) {
for (int grantResult : grantResults) {
if (grantResult == PackageManager.PERMISSION_DENIED) {
return false;
}
}
return true;
}
// 显示缺失权限提示
private void showMissingPermissionDialog() {
AlertDialog.Builder builder = new AlertDialog.Builder(PermissionsActivity.this);
builder.setTitle(R.string.help);
builder.setMessage(R.string.string_help_text);
// 拒绝, 退出应用
builder.setNegativeButton(R.string.quit, new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialog, int which) {
setResult(PERMISSIONS_DENIED);
finish();
}
});
builder.setPositiveButton(R.string.settings, new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialog, int which) {
startAppSettings();
}
});
builder.show();
}
// 启动应用的设置
private void startAppSettings() {
Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
intent.setData(Uri.parse(PACKAGE_URL_SCHEME + getPackageName()));
startActivity(intent);
}
}
所需的Strings文件如下：
<string name="help">帮助</string>
<string name="string_help_text">当前应用缺少必要权限。\n\n请点击\"设置\"-\"权限\"-打开所需权限。\n\n最后点击两次后退按钮，即可返回。</string>
<string name="quit">退出</string>
<string name="settings">设置</string>
所需的layout文件：
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.maywide.cmms.gcableboss.util.PermissionsActivity">
</android.support.constraint.ConstraintLayout>
一般在程序启动时进行权限判断：
//权限数组
static final String[] PERMISSIONS = new String[]{
Manifest.permission.WRITE_EXTERNAL_STORAGE,
Manifest.permission.CAMERA,
Manifest.permission.READ_EXTERNAL_STORAGE,
};
//检测权限
private PermissionsChecker permissionsChecker;
private int REQUEST_CODE = 0;
permissionsChecker = new PermissionsChecker(this);
// 缺少权限时, 进入权限配置页面
if (permissionsChecker.lacksPermissions(PERMISSIONS)) {
startPermissionsActivity();
}
/**
* 权限检测
*/
private void startPermissionsActivity() {
PermissionsActivity.startActivityForResult(this, REQUEST_CODE, PERMISSIONS);
}
