the logcat shows something like button does not exist,but i couldn't find any mistake there.
The app force closes when i click the flashlight button in the main activity page.
I am new to android programming. please help.
LogCat:
02-04 21:36:29.182: E/AndroidRuntime(798): FATAL EXCEPTION: main
02-04 21:36:29.182: E/AndroidRuntime(798): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.iamtheonewhoknocks.toolkit/com.iamtheonewhoknocks.toolkit.FlashlightActivity}: java.lang.IllegalArgumentException: Button does not exist
02-04 21:36:29.182: E/AndroidRuntime(798): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
02-04 21:36:29.182: E/AndroidRuntime(798): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
02-04 21:36:29.182: E/AndroidRuntime(798): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-04 21:36:29.182: E/AndroidRuntime(798): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
02-04 21:36:29.182: E/AndroidRuntime(798): at android.os.Handler.dispatchMessage(Handler.java:99)
02-04 21:36:29.182: E/AndroidRuntime(798): at android.os.Looper.loop(Looper.java:123)
02-04 21:36:29.182: E/AndroidRuntime(798): at android.app.ActivityThread.main(ActivityThread.java:3683)
02-04 21:36:29.182: E/AndroidRuntime(798): at java.lang.reflect.Method.invokeNative(Native Method)
02-04 21:36:29.182: E/AndroidRuntime(798): at java.lang.reflect.Method.invoke(Method.java:507)
02-04 21:36:29.182: E/AndroidRuntime(798): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-04 21:36:29.182: E/AndroidRuntime(798): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-04 21:36:29.182: E/AndroidRuntime(798): at dalvik.system.NativeStart.main(Native Method)
02-04 21:36:29.182: E/AndroidRuntime(798): Caused by: java.lang.IllegalArgumentException: Button does not exist
02-04 21:36:29.182: E/AndroidRuntime(798): at com.android.internal.app.AlertController.setButton(AlertController.java:288)
02-04 21:36:29.182: E/AndroidRuntime(798): at android.app.AlertDialog.setButton(AlertDialog.java:161)
02-04 21:36:29.182: E/AndroidRuntime(798): at com.iamtheonewhoknocks.toolkit.FlashlightActivity.onCreate(FlashlightActivity.java:42)
02-04 21:36:29.182: E/AndroidRuntime(798): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-04 21:36:29.182: E/AndroidRuntime(798): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
02-04 21:36:29.182: E/AndroidRuntime(798): ... 11 more
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#151515"
android:orientation="horizontal"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:focusable="true"
tools:context=".MainActivity" >
<ImageButton
android:id="@+id/flashButton"
android:layout_width="60dip"
android:layout_height="60dip"
android:background="@drawable/flashlight"
android:contentDescription="@string/flashlighticon"
android:drawableTop="@drawable/flashlight" />
<ImageButton
android:id="@+id/convertorButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/flashButton"
android:layout_centerHorizontal="true"
android:background="@drawable/converter"
android:contentDescription="@string/convertericon" />
<ImageButton
android:id="@+id/mglassButton"
android:layout_width="60dip"
android:layout_height="60dip"
android:layout_alignLeft="@+id/compassButton"
android:layout_alignTop="@+id/mirrorButton"
android:background="@drawable/mglass"
android:contentDescription="@string/mglassicon" />
<ImageButton
android:id="@+id/bubbleButton"
android:layout_width="60dip"
android:layout_height="60dip"
android:layout_alignLeft="@+id/convertorButton"
android:layout_below="@+id/flashButton"
android:layout_marginTop="87dp"
android:background="@drawable/bubble"
android:contentDescription="@string/bubbleicon" />
<ImageButton
android:id="@+id/compassButton"
android:layout_width="60dip"
android:layout_height="60dip"
android:layout_above="@+id/mirrorButton"
android:layout_alignLeft="@+id/flashButton"
android:background="@drawable/compass"
android:contentDescription="@string/compassicon" />
<ImageButton
android:id="@+id/mirrorButton"
android:layout_width="60dip"
android:layout_height="60dip"
android:layout_alignLeft="@+id/bubbleButton"
android:layout_below="@+id/bubbleButton"
android:layout_marginTop="83dp"
android:background="@drawable/mirror"
android:contentDescription="@string/mirroricon" />
<ImageButton
android:id="@+id/timerButton"
android:layout_width="60dip"
android:layout_height="60dip"
android:layout_above="@+id/bubbleButton"
android:layout_alignLeft="@+id/calcButton"
android:background="@drawable/timer"
android:contentDescription="@string/timericon" />
<ImageButton
android:id="@+id/calcButton"
android:layout_width="60dip"
android:layout_height="60dip"
android:layout_above="@+id/mirrorButton"
android:layout_alignParentRight="true"
android:background="@drawable/calculator"
android:contentDescription="@string/calcicon" />
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/flashButton"
android:layout_below="@+id/flashButton"
android:layout_marginTop="19dp"
android:gravity="center"
android:text="@string/flashlighticon"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/compassButton"
android:layout_below="@+id/compassButton"
android:layout_marginTop="17dp"
android:gravity="center"
android:text="@string/compassicon"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/textView6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView5"
android:layout_alignBottom="@+id/textView5"
android:layout_alignRight="@+id/calcButton"
android:gravity="center"
android:text="@string/calcicon"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/textView7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/mglassButton"
android:layout_below="@+id/mglassButton"
android:layout_marginTop="16dp"
android:gravity="center"
android:text="@string/mglassicon"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/textView8"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView7"
android:layout_alignBottom="@+id/textView7"
android:layout_alignLeft="@+id/mirrorButton"
android:layout_alignRight="@+id/textView5"
android:gravity="center"
android:text="@string/mirroricon"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView2"
android:layout_alignBottom="@+id/textView2"
android:layout_alignLeft="@+id/timerButton"
android:layout_alignRight="@+id/timerButton"
android:gravity="center"
android:text="@string/timericon"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView1"
android:layout_alignBottom="@+id/textView1"
android:layout_centerHorizontal="true"
android:gravity="center"
android:text="@string/convertericon"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView4"
android:layout_alignBottom="@+id/textView4"
android:layout_alignRight="@+id/textView2"
android:gravity="center"
android:text="@string/bubbleicon"
android:textAppearance="?android:attr/textAppearanceSmall" />
</RelativeLayout>
MainActivity.java
package com.iamtheonewhoknocks.toolkit;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.View;
import android.widget.ImageButton;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
flashlightButton();
calculatorButton();
bubbleButton();
}
private void flashlightButton()
{ ImageButton flButton= (ImageButton) findViewById(R.id.flashButton);
flButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(MainActivity.this,FlashlightActivity.class));
}
});
}
private void calculatorButton()
{ ImageButton flButton= (ImageButton) findViewById(R.id.calcButton);
flButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(MainActivity.this,CalculatorActivity.class));
}
});
}
private void bubbleButton()
{ ImageButton flButton= (ImageButton) findViewById(R.id.bubbleButton);
flButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(MainActivity.this,BubbleActivity.class));
}
});
}
/*@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
} */
}
activity_flashlight.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#000000"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".FlashlightActivity" >
<ImageButton
android:id="@+id/btnSwitch"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:background="@drawable/flashlight_off"
android:contentDescription="@null" />
</RelativeLayout>
FlashlightActivity.java
package com.iamtheonewhoknocks.toolkit;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ImageButton;
//import android.view.View.OnClickListener;
public class FlashlightActivity extends Activity {
ImageButton switchButton;
private Camera camera;
private boolean isFlashOn;
private boolean hasFlash;
Parameters params;
MediaPlayer mp;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_flashlight);
switchButton = (ImageButton) findViewById(R.id.btnSwitch);
// 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(FlashlightActivity.this)
.create();
alert.setTitle("Error");
alert.setMessage("Sorry, your device doesn't support flash light!");
alert.setButton(0,"OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// closing the application
finish();
}
});
alert.show();
return;
}
// get the camera
getCamera();
// displaying button image
toggleButtonImage();
// Switch button click event to toggle flash on/off
switchButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (isFlashOn) {
// turn off flash
turnOffFlash();
} else {
// turn on flash
turnOnFlash();
}
}
});
}
// 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;
}
// play sound
// playSound();
params = camera.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(params);
camera.startPreview();
isFlashOn = true;
// changing button/switch image
toggleButtonImage();
}
}
// Turning Off flash
private void turnOffFlash() {
if (isFlashOn) {
if (camera == null || params == null) {
return;
}
// play sound
// playSound();
params = camera.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(params);
camera.stopPreview();
isFlashOn = false;
// changing button/switch image
toggleButtonImage();
}
}
/*
* Toggle switch button images
* changing image states to on / off
* */
private void toggleButtonImage(){
if(isFlashOn){
switchButton.setImageResource(R.drawable.flashlight_on);
}else{
switchButton.setImageResource(R.drawable.flashlight_off);
}
}
@Override
protected void onDestroy() {
super.onDestroy();
}
@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();
// on resume turn on the flash
if(hasFlash)
turnOnFlash();
}
@Override
protected void onStart() {
super.onStart();
// on starting the app get the camera params
getCamera();
}
@Override
protected void onStop() {
super.onStop();
// on stop release the camera
if (camera != null) {
camera.release();
camera = null;
}
}
/*
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.flashlight, menu);
return true;
} */
}
manifest file
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.iamtheonewhoknocks.toolkit"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.iamtheonewhoknocks.toolkit.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.iamtheonewhoknocks.toolkit.FlashlightActivity"
android:label="@string/title_activity_flashlight" >
</activity>
<activity
android:name="com.iamtheonewhoknocks.toolkit.CalculatorActivity"
android:label="@string/title_activity_calculator" >
</activity>
<activity
android:name="com.iamtheonewhoknocks.toolkit.TimerActivity"
android:label="@string/title_activity_timer" >
</activity>
<activity
android:name="com.iamtheonewhoknocks.toolkit.BubbleActivity"
android:label="@string/title_activity_bubble" >
</activity>
</application>
</manifest>