How to link a button in xml to the java actions in a class

Question

very new to developing!

I basically want to link a button that I have created in XML to the java code in the respective class.

What I am trying to achieve is a button that is placed above my webview that has text "Start Recording" once clicked the audio record function will start, and the text will then change to "Stop Recording".

The issue that I am having, is that I have a button in the screen on my app, however, there is no text on it and when I click the button my app crashes.

The following is the code for the class:

public class Drugs extends AppCompatActivity {

WebView myBrowser;

private static final String LOG_TAG = "Recording";
private static String mFileName = null;


private RecordButton mRecordButton = null;
private MediaRecorder mRecorder = null;

private void onRecord(boolean start) {
    if (start) {
        startRecording();
    } else {
        stopRecording();
    }
}

private void startRecording() {
    mRecorder = new MediaRecorder();
    mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
    mRecorder.setOutputFile(mFileName);
    mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

    try {
        mRecorder.prepare();
    } catch (IOException e) {
        Log.e(LOG_TAG, "prepare() failed");
    }

    mRecorder.start();
}

private void stopRecording() {
    mRecorder.stop();
    mRecorder.release();
    mRecorder = null;
}

class RecordButton extends Button {
    boolean mStartRecording = true;

    OnClickListener clicker = new OnClickListener() {
        public void onClick(View v) {
            onRecord(mStartRecording);
            if (mStartRecording) {
                setText("Stop recording");
            } else {
                setText("Start recording");
            }
            mStartRecording = !mStartRecording;
        }
    };

    public RecordButton(Context ctx) {
        super(ctx);
        setText("Start recording");
        setOnClickListener(clicker);
    }
}

public Drugs() {
    mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
    mFileName += "/audiorecordtest.3gp";
}





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

    myBrowser = (WebView) findViewById(R.id.mybrowser);
    myBrowser.loadUrl("file:///android_asset/drugs.html");
    myBrowser.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);

    Button btndrugslaw = (Button) findViewById(R.id.drugslaw);

    btndrugslaw.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            Intent intentdruglaw = new Intent(Drugs.this, DrugLaw.class);
            startActivity(intentdruglaw);
        }
    });

}

This is the code for xml

<ScrollView
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent">

<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"
tools:context="kyr.com.knowyourrights.Drugs"
android:orientation="vertical"
>

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/RecordButton"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:onClick="onClick"
    >

</Button>

<WebView
    android:id="@+id/mybrowser"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
  >

</WebView>

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/drugslaw"
    android:text="Take me to the law"
    android:layout_below="@id/mybrowser"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true" />

</RelativeLayout>


</ScrollView>

Atiq · Accepted Answer · 2016-05-11 04:48:57Z

1

There are many ways.

For example

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/RecordButton"
    android:layout_above="@+id/mybrowser"
    android:layout_alignParentTop="true"
    android:onClick="recordClick"
    android:layout_centerHorizontal="true">

and then in your class

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

    myBrowser = (WebView) findViewById(R.id.mybrowser);
    myBrowser.loadUrl("file:///android_asset/drugs.html");
    myBrowser.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);

    Button btndrugslaw = (Button) findViewById(R.id.drugslaw);

    btndrugslaw.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            Intent intentdruglaw = new Intent(Drugs.this, DrugLaw.class);
            startActivity(intentdruglaw);
        }
    });

public void recordClick(View view){

    // your code to handle click
}

}

and if you have multiple buttons

    public void recordClick(View view){

    switch(view.getId())

    //HERE YOU WILL PASS THE ID OF YOUR BUTTONS
    case R.id.firstButton:
        //Code to handle click
    case R.id.secondButton:
        //Code to handle second button click

    // AND SO ON
}

answered May 11, 2016 at 4:48

Atiq

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4 Comments

Viverson Over a year ago

I only have two buttons, one button at the bottom of the webview that takes me to a new activity - which is coded and works fine (R.id.drugslaw) and there is one button that handles the recording function. I believe I have the code properly to record (unless I don't) but when I enter the corresponding screen on my application, there is no button that appears for the record function. @Anders

Atiq Over a year ago

so you saying you button is not visible?

Viverson Over a year ago

Yeah I cant see the button

Viverson Over a year ago

I can now see the button, but there is no text on the button and when I click it, my app crashes

Venky · Accepted Answer · 2016-05-11 04:56:12Z

Add OnClick method in XML

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/RecordButton"
    android:layout_above="@+id/mybrowser"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:onClick="RecordButton"
    android:text="Start"
    >

In Java

    Button btn = (Button) findViewById(R.id.RecordButton);

    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
        RecordButton(v);
        }
    });


    public void RecordButton(View v) {
           Button b = (Button)v;
          if(b.getText().toString().equals("Start")){
             onRecord(true);
             b.setText("Stop");
          }else{
             onRecord(false);
             b.setText("Start");
    }

Nouman Shah · Accepted Answer · 2016-05-11 05:09:22Z

0

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/RecordButton"
    android:layout_above="@+id/mybrowser"
    android:layout_alignParentTop="true"
    android:onClick="recordClick"
    android:layout_centerHorizontal="true">

Implements the View.OnClickLIstener

public class Drugs extends AppCompatActivity implements View.OnClickListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_drugs);
    Button btndrugs = (Button) findViewById(R.id.RecordButton);
    btndurgs.setOnClickListener(this);
      }
   public void onClick(View v) {
        switch (v.getId()){
            case(R.id.RecordButton):
your logic here
    break;
    }
}}

answered May 11, 2016 at 5:09

Nouman Shah

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2 Comments

Viverson Over a year ago

When I do this, my onRecord boolean cannot be solved. I am trying to get one button that has the test "Start Recording" which when clicked records audio, then the text on the same button will change to "Stop Recording" when clicked it will stop recording

Nouman Shah Over a year ago

make your boolean variable static and for changing text your_button.setText(" ");

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