Question

当我构建项目时，我选择了android 4.0.3 IceCreamSandwich。之后我安装在android os.6和android os.4手机上。我意识到只适用于操作系统4，较新的API不能支持旧的API？这听起来不是逻辑.........

Andoird表现

rn = 2

Android Main

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.jackd.testflash_26_4_2017">

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />

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

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

Android XML布局

package com.example.jackd.testflash_26_4_2017;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private Camera camera;
    private Camera.Parameters params;
    Button btnFlash;
    TextView txtArea,txtArea2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        btnFlash = (Button) findViewById(R.id.btnFlash);

        final String myString = "110101010101";
        final long blinkDelay = 50;



    btnFlash.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            for(int i = 0;i<myString.length();i++){

                if(myString.charAt(i) == '0'){

                   params.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
                    camera.setParameters(params);
                    camera.startPreview();
                }
                else{
                    params.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
                    camera.setParameters(params);
                    camera.stopPreview();
                }
                try{
                    Thread.sleep(blinkDelay);
                }catch(InterruptedException e){
                    e.printStackTrace();
                }
            }
        }
    });
    if (isFlashSupported()) {
        camera = Camera.open();
        params = camera.getParameters();
    } else {
        showNoFlashAlert();
    }
}


private void showNoFlashAlert() {
    new AlertDialog.Builder(this)
            .setMessage("Your device hardware does not support flashlight!")
            .setIcon(android.R.drawable.ic_dialog_alert).setTitle("Error")
            .setPositiveButton("Ok", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.dismiss();
                    finish();
                }
            }).show();
}
private boolean isFlashSupported() {
    PackageManager pm = getPackageManager();
    return pm.hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);
}
@Override
protected void onDestroy() {
    if(camera != null){
        camera.stopPreview();
        camera.release();
        camera = null;
    }
    super.onDestroy();
}

}

PS：我已经打开了相机硬件的所有权限。在OS6中，它需要手动打开，我已经做到了！

回到问题，Version6 Marshmallow android不能支持version4 iceCreamSandwith吗？但是，逻辑上更高的版本应该支持更低版本....感谢您的帮助！

Answer 1

android开发者：

从Android 6.0（API级别23）开始，用户授予权限应用程序运行时的应用程序，而非安装应用程序时的应用程序。

您可以查看此信息以获取更多信息：

https://developer.android.com/training/permissions/requesting.html

Android OS 6 Marshallow无法在相机上运行4.0.3版应用程序？

1 个答案: