added sine wave demo 3

JackJiang42 · Aug 14, 2019 · c997e63 · c997e63
1 parent 783656a
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diff --git a/Android_Demos/java_implementations/Sine_Wave_Demo3/MainActivity.java b/Android_Demos/java_implementations/Sine_Wave_Demo3/MainActivity.java
@@ -0,0 +1,116 @@
+import android.support.v7.app.AppCompatActivity;
+import android.os.Bundle;
+import android.view.View;
+import android.widget.Button;
+import android.media.AudioTrack;
+import android.media.AudioFormat;
+import android.media.AudioManager;
+import android.widget.SeekBar;
+import android.widget.TextView;
+
+public class MainActivity extends AppCompatActivity {
+
+    Button PlayBtn;
+    Button StopBtn;
+    SeekBar FreqSlider;
+    TextView FreqDisp;
+    AudioTrack Track;
+    boolean isplaying = false;
+    int Fs = 44100;
+    int frequency = 500;
+    int  buffLength = AudioTrack.getMinBufferSize(Fs, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+
+        PlayBtn = (Button) findViewById(R.id.PlayBtn);
+        PlayBtn.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                if (!isplaying){
+                    (new Thread() {
+                        @Override
+                        public void run() {
+                            initTrack();
+                            startPlaying();
+                            playback();
+                        }
+                    }).start();
+                }
+
+            }
+        });
+
+        StopBtn = (Button) findViewById(R.id.StopBtn);
+        StopBtn.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                stopPlaying();
+            }
+        });
+
+        FreqDisp = (TextView) findViewById(R.id.FreqDisp);
+        FreqSlider = (SeekBar) findViewById(R.id.FreqSlider);
+        FreqSlider.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
+            @Override
+            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
+                String disp_msg="";
+                frequency = i;
+                disp_msg +=frequency;
+                FreqDisp.setText(disp_msg);
+            }
+
+            @Override
+            public void onStartTrackingTouch(SeekBar seekBar) {
+
+            }
+
+            @Override
+            public void onStopTrackingTouch(SeekBar seekBar) {
+
+            }
+        });
+    }
+
+    private void initTrack(){
+
+        Track = new AudioTrack(AudioManager.MODE_NORMAL,
+                Fs,
+                AudioFormat.CHANNEL_OUT_MONO,
+                AudioFormat.ENCODING_PCM_16BIT,
+                buffLength,
+                AudioTrack.MODE_STREAM);
+    }
+
+    private void startPlaying(){
+        Track.play();
+        isplaying=true;
+    }
+
+    private void playback(){
+        short[] frame_out= new short[buffLength];
+        int amplitude = (int) (32767) ;
+        double twopi = 8. * Math.atan(1.);
+        double phase = 0.0;
+        while (isplaying){
+            for (int i = 0; i < buffLength; i++) {
+                frame_out[i] = (short) (amplitude * Math.sin(phase));
+                phase += twopi * frequency / Fs;
+                if (phase>twopi){
+                    phase -= twopi;
+                }
+            }
+            Track.write(frame_out, 0, buffLength);
+        }
+    }
+
+    private void stopPlaying(){
+        if (isplaying){
+            isplaying=false;
+            Track.stop();
+            Track.release();
+        }
+    }
+}
diff --git a/Android_Demos/java_implementations/Sine_Wave_Demo3/README.md b/Android_Demos/java_implementations/Sine_Wave_Demo3/README.md
@@ -0,0 +1,185 @@
+# Sine Wave Demo - 3 (Java)
+
+This is demo is similar to `Sine Wave Demo - 2` which supported changing frequency of sine wave using Buttons.
+Instead of buttons, this demo uses Slider which was used in the `Slider Demo`. Slider provides a convenient way to vary the frequency.
+
+**MainActivity.java**
+
+```java
+import android.support.v7.app.AppCompatActivity;
+import android.os.Bundle;
+import android.view.View;
+import android.widget.Button;
+import android.media.AudioTrack;
+import android.media.AudioFormat;
+import android.media.AudioManager;
+import android.widget.SeekBar;
+import android.widget.TextView;
+
+public class MainActivity extends AppCompatActivity {
+
+    Button PlayBtn;
+    Button StopBtn;
+    SeekBar FreqSlider;
+    TextView FreqDisp;
+    AudioTrack Track;
+    boolean isplaying = false;
+    int Fs = 44100;
+    int frequency = 500;
+    int  buffLength = AudioTrack.getMinBufferSize(Fs, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+
+        PlayBtn = (Button) findViewById(R.id.PlayBtn);
+        PlayBtn.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                if (!isplaying){
+                    (new Thread() {
+                        @Override
+                        public void run() {
+                            initTrack();
+                            startPlaying();
+                            playback();
+                        }
+                    }).start();
+                }
+
+            }
+        });
+
+        StopBtn = (Button) findViewById(R.id.StopBtn);
+        StopBtn.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                stopPlaying();
+            }
+        });
+
+        FreqDisp = (TextView) findViewById(R.id.FreqDisp);
+        FreqSlider = (SeekBar) findViewById(R.id.FreqSlider);
+        FreqSlider.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
+            @Override
+            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
+                String disp_msg="";
+                frequency = i;
+                disp_msg +=frequency;
+                FreqDisp.setText(disp_msg);
+            }
+
+            @Override
+            public void onStartTrackingTouch(SeekBar seekBar) {
+
+            }
+
+            @Override
+            public void onStopTrackingTouch(SeekBar seekBar) {
+
+            }
+        });
+    }
+
+    private void initTrack(){
+
+        Track = new AudioTrack(AudioManager.MODE_NORMAL,
+                Fs,
+                AudioFormat.CHANNEL_OUT_MONO,
+                AudioFormat.ENCODING_PCM_16BIT,
+                buffLength,
+                AudioTrack.MODE_STREAM);
+    }
+
+    private void startPlaying(){
+        Track.play();
+        isplaying=true;
+    }
+
+    private void playback(){
+        short[] frame_out= new short[buffLength];
+        int amplitude = (int) (32767) ;
+        double twopi = 8. * Math.atan(1.);
+        double phase = 0.0;
+        while (isplaying){
+            for (int i = 0; i < buffLength; i++) {
+                frame_out[i] = (short) (amplitude * Math.sin(phase));
+                phase += twopi * frequency / Fs;
+                if (phase>twopi){
+                    phase -= twopi;
+                }
+            }
+            Track.write(frame_out, 0, buffLength);
+        }
+    }
+
+    private void stopPlaying(){
+        if (isplaying){
+            isplaying=false;
+            Track.stop();
+            Track.release();
+        }
+    }
+}
+```
+
+**activity_main.XML**
+
+```xml
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout 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=".MainActivity"
+    android:gravity="center_horizontal"
+    android:orientation="vertical">
+
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="20dp"
+        android:text="Demo plays sine function!"
+        android:textSize="30dp"
+        />
+    <Button
+        android:id="@+id/PlayBtn"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="30dp"
+        android:text="play"
+        android:textSize="20dp"/>
+    <Button
+        android:id="@+id/StopBtn"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Stop"
+        android:textSize="20dp"/>
+
+    <SeekBar
+        android:id="@+id/FreqSlider"
+        android:layout_width="300dp"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="40dp"
+        android:progress="500"
+        android:max="1000"
+        />
+
+    <TextView
+        android:id="@+id/FreqDisp"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="30dp"
+        android:text="500"
+        android:textSize="25dp"/>
+
+</LinearLayout>
+```
+
+## Screenshots
+
+Following are few screenshots of this demo.
+
+![1](../../../images/screenshots/sine_wave_demo3_1.png)
diff --git a/Android_Demos/java_implementations/Sine_Wave_Demo3/activity_main.xml b/Android_Demos/java_implementations/Sine_Wave_Demo3/activity_main.xml
@@ -0,0 +1,49 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout 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=".MainActivity"
+    android:gravity="center_horizontal"
+    android:orientation="vertical">
+
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="20dp"
+        android:text="Demo plays sine function!"
+        android:textSize="30dp"
+        />
+    <Button
+        android:id="@+id/PlayBtn"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="30dp"
+        android:text="play"
+        android:textSize="20dp"/>
+    <Button
+        android:id="@+id/StopBtn"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Stop"
+        android:textSize="20dp"/>
+
+    <SeekBar
+        android:id="@+id/FreqSlider"
+        android:layout_width="300dp"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="40dp"
+        android:progress="500"
+        android:max="1000"
+        />
+
+    <TextView
+        android:id="@+id/FreqDisp"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="30dp"
+        android:text="500"
+        android:textSize="25dp"/>
+
+</LinearLayout>