Netkiller Android 手札

http://www.netkiller.cn/android/index.html

Mr. Neo Chan, 陈景峯(BG7NYT)

中国广东省深圳市望海路半岛城邦三期
518067
+86 13113668890

<netkiller@msn.com>

$Id: book.xml 606 2013-05-29 09:52:58Z netkiller $

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2018-10

我的系列文档

编程语言

10.4. LED flash 做手电筒

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

<?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=".FlashLightActivity"><Buttonandroid:id="@+id/buttonLight"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginStart="8dp"android:layout_marginTop="8dp"android:layout_marginEnd="8dp"android:layout_marginBottom="8dp"android:text="On"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

package cn.netkiller.camera;import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;import java.security.Policy;public class FlashLightActivity extends AppCompatActivity {private Button buttonLight;private CameraManager cameraManager;private String cameraId;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_flash_light);buttonLight = (Button) findViewById(R.id.buttonLight);Boolean isFlashAvailable = getApplicationContext().getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);if (!isFlashAvailable) {AlertDialog alert = new AlertDialog.Builder(FlashLightActivity.this).create();alert.setTitle("Error");alert.setMessage("Your device doesn't support flash light!");alert.setButton(DialogInterface.BUTTON_POSITIVE, "OK", new DialogInterface.OnClickListener() {public void onClick(DialogInterface dialog, int which) {// closing the applicationfinish();System.exit(0);}});alert.show();return;}cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);try {cameraId = cameraManager.getCameraIdList()[0];} catch (CameraAccessException e) {e.printStackTrace();}buttonLight.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {try {light();} catch (CameraAccessException e) {e.printStackTrace();}}});}public void light() throws CameraAccessException {if (buttonLight.getText().equals("On")) {Toast.makeText(getApplicationContext(), "打开手电筒", Toast.LENGTH_SHORT).show();cameraManager.setTorchMode(cameraId, true);buttonLight.setText("Off");} else {Toast.makeText(getApplicationContext(), "关闭手电筒", Toast.LENGTH_SHORT).show();cameraManager.setTorchMode(cameraId, false);buttonLight.setText("On");}}
}

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