Android Flashlight Application

  

Let's Create a new project

1. Create a new project in Android Studio by going to File ⇒ New ⇒ Android Application Project . I named my package as tp.com.fahim and main activity as MainActivity.java 2. Open your AndroidManifest.xml file and add required permissions. I also disabled landscape mode in manifest file by using android:screenOrientation=”portrait” property. android.permission.CAMERA – required to access the camera device android.hardware.camera – required to access camera hardware features AndroidManifest.xml <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="tp.com.fahim"> <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> </manifest> 3. Place all the switch image files under drawable-hdpi, drawable-mdpi, drawable-ldpi folders. I named switch image files as btn_switch_off.png and btn_switch_on.png 4. Open activity_main.xml file located under res ⇒ layout folder and type the following code. This layout file acts as main screen of the application. Activity_main.xml <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="tp.com.fahim.MainActivity"> <ImageView android:id="@+id/imageView" android:layout_width="300dp" android:layout_height="300dp" android:layout_margin="0dp" android:src="@drawable/pic_bulboff" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" /> <Switch android:id="@+id/switch1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_centerHorizontal="true" android:layout_marginBottom="44dp" android:text="ON" /> </RelativeLayout> 5. Open your MainActivity.java file and do the following changes.

Final Code

MainActivity.java package tp.com.fahim; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.pm.PackageManager; import android.hardware.Camera; import android.hardware.Camera.Parameters; import android.os.Bundle; import android.support.v4.widget.DrawerLayout; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.view.View; import android.widget.CompoundButton; import android.widget.ImageView; import android.widget.Switch; import android.widget.TextView; public class MainActivity extends AppCompatActivity { Switch btnSwitch; ImageView img; private Camera camera; private boolean isFlashOn; private boolean hasFlash; Parameters params; private static int flag=1; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // flash switch button btnSwitch = (Switch) findViewById(R.id.switch1); img = (ImageView) findViewById(R.id.imageView); // First check if device is supporting flashlight or not hasFlash = getApplicationContext().getPackageManager() .hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH); if (!hasFlash) { // device doesn't support flash // Show alert message and close the application AlertDialog alert = new AlertDialog.Builder(MainActivity.this) .create(); alert.setTitle("Error"); alert.setMessage("Sorry, your device doesn't support flash light!"); alert.setButton("OK", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { // closing the application finish(); } }); alert.show(); return; } // get the camera getCamera(); // Switch button click event to toggle flash on/off btnSwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { if (btnSwitch.isChecked()) { turnOnFlash(); flag=1; } else { turnOffFlash(); flag=0; } } }); img.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if(flag==0) btnSwitch.setChecked(true); else btnSwitch.setChecked(false); } }); } // Get the camera private void getCamera() { if (camera == null) { try { camera = Camera.open(); params = camera.getParameters(); } catch (RuntimeException e) { Log.e("Camera Error. Failed to Open. Error: ", e.getMessage()); } } } // Turning On flash private void turnOnFlash() { if (!isFlashOn) { if (camera == null || params == null) { return; } params = camera.getParameters(); params.setFlashMode(Parameters.FLASH_MODE_TORCH); camera.setParameters(params); camera.startPreview(); isFlashOn = true; // changing button/switch image & text img.setImageResource(R.drawable.pic_bulbon); btnSwitch.setText("OFF"); } } // Turning Off flash private void turnOffFlash() { if (isFlashOn) { if (camera == null || params == null) { return; } params = camera.getParameters(); params.setFlashMode(Parameters.FLASH_MODE_OFF); camera.setParameters(params); camera.stopPreview(); isFlashOn = false; // changing button/switch image img.setImageResource(R.drawable.pic_bulboff); btnSwitch.setText("ON"); } } @Override protected void onDestroy() { super.onDestroy(); camera.release(); params=null; } @Override protected void onPause() { super.onPause(); // on pause turn off the flash // turnOffFlash(); } @Override protected void onRestart() { super.onRestart(); } @Override protected void onResume() { super.onResume(); if(flag==1) btnSwitch.setChecked(true); if (flag==0) btnSwitch.setChecked(false); } @Override protected void onStart() { super.onStart(); getCamera(); // on starting the app get the camera params } @Override protected void onStop() { super.onStop(); } }