为代码添加权限检查

 import android.content.Context;
import android.content.pm.PackageManager;

public class Hello {

public static final String PERMISSION_SAY_HELLO = "com.example.authoritydemo.permission.SAY_HELLO";

public static void sayHello(Context cxt) {
int checkResult = cxt.checkCallingOrSelfPermission(PERMISSION_SAY_HELLO);
// 判断是否被允许
if (checkResult != PackageManager.PERMISSION_GRANTED) {
throw new SecurityException("执行方法需要com.example.authoritydemo.permission.SAY_HELLO权限");
}
System.out.println("Say Hello www.baidu.com");
}

}

 public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

Hello.sayHello(this);
}

}

    <permission android:name="com.example.authoritydemo.permission.SAY_HELLO" />
<uses-permission android:name="com.example.authoritydemo.permission.SAY_HELLO" />