I'm not completely sure what your question is, but I'll assume you're wondering how to make your app. You'll need a textview for the lyrics and a button beneath it. When the button is clicked, the app will randomly choose a song from a list of songs and display the song's lyrics in the textview.
I created an app that does those things, as an example. Below is the activity-main.xml file. Replace YOUR-PACKAGE-NAME with your package name (e.g. com.example.whatever).
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:id="@+id/layout"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
<YOUR-PACKAGE-NAME.AutoResizeTextView
android:id="@+id/textview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="1000sp"
android:gravity="center"
android:maxLines="4"
android:text="Row row, row your boat \n Gently down the stream \n Merrily, merrily, merrily, merrily \n Life is but a dream"/>
<!--Above you should enter the song that will appear first -->
<!--In maxLines put the number of lines the starting song is-->
<Button
android:id="@+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/textview"
android:text="Click for Random Song"
android:textSize="25sp"/>
Create a new class called AutoResizeTextView and paste this code below your package line. I took this from the stackoverflow answer at https://stackoverflow.com/a/17782522/5260943
import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.RectF;
import android.os.Build;
import android.text.Layout.Alignment;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.util.SparseIntArray;
import android.util.TypedValue;
import android.widget.TextView;
public class AutoResizeTextView extends TextView {
private interface SizeTester {
/**
*
* @param suggestedSize
* Size of text to be tested
* @param availableSpace
* available space in which text must fit
* @return an integer < 0 if after applying {@code suggestedSize} to
* text, it takes less space than {@code availableSpace}, > 0
* otherwise
*/
public int onTestSize(int suggestedSize, RectF availableSpace);
}
private RectF mTextRect = new RectF();
private RectF mAvailableSpaceRect;
private SparseIntArray mTextCachedSizes;
private TextPaint mPaint;
private float mMaxTextSize;
private float mSpacingMult = 1.0f;
private float mSpacingAdd = 0.0f;
private float mMinTextSize = 20;
private int mWidthLimit;
private static final int NO_LINE_LIMIT = -1;
private int mMaxLines;
private boolean mEnableSizeCache = true;
private boolean mInitiallized;
public AutoResizeTextView(Context context) {
super(context);
initialize();
}
public AutoResizeTextView(Context context, AttributeSet attrs) {
super(context, attrs);
initialize();
}
public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
initialize();
}
public void initialize() {
mPaint = new TextPaint(getPaint());
mMaxTextSize = getTextSize();
mAvailableSpaceRect = new RectF();
mTextCachedSizes = new SparseIntArray();
if (mMaxLines == 0) {
// no value was assigned during construction
mMaxLines = NO_LINE_LIMIT;
}
mInitiallized = true;
}
@Override
public void setText(final CharSequence text, BufferType type) {
super.setText(text, type);
adjustTextSize(text.toString());
}
@Override
public void setTextSize(float size) {
mMaxTextSize = size;
mTextCachedSizes.clear();
adjustTextSize(getText().toString());
}
@Override
public void setMaxLines(int maxlines) {
super.setMaxLines(maxlines);
mMaxLines = maxlines;
reAdjust();
}
public int getMaxLines() {
return mMaxLines;
}
@Override
public void setSingleLine() {
super.setSingleLine();
mMaxLines = 1;
reAdjust();
}
@Override
public void setSingleLine(boolean singleLine) {
super.setSingleLine(singleLine);
if (singleLine) {
mMaxLines = 1;
} else {
mMaxLines = NO_LINE_LIMIT;
}
reAdjust();
}
@Override
public void setLines(int lines) {
super.setLines(lines);
mMaxLines = lines;
reAdjust();
}
@Override
public void setTextSize(int unit, float size) {
Context c = getContext();
Resources r;
if (c == null)
r = Resources.getSystem();
else
r = c.getResources();
mMaxTextSize = TypedValue.applyDimension(unit, size,
r.getDisplayMetrics());
mTextCachedSizes.clear();
adjustTextSize(getText().toString());
}
@Override
public void setLineSpacing(float add, float mult) {
super.setLineSpacing(add, mult);
mSpacingMult = mult;
mSpacingAdd = add;
}
/**
* Set the lower text size limit and invalidate the view
*
* @param minTextSize
*/
public void setMinTextSize(float minTextSize) {
mMinTextSize = minTextSize;
reAdjust();
}
private void reAdjust() {
adjustTextSize(getText().toString());
}
private void adjustTextSize(String string) {
if (!mInitiallized) {
return;
}
int startSize = (int) mMinTextSize;
int heightLimit = getMeasuredHeight() - getCompoundPaddingBottom()
- getCompoundPaddingTop();
mWidthLimit = getMeasuredWidth() - getCompoundPaddingLeft()
- getCompoundPaddingRight();
mAvailableSpaceRect.right = mWidthLimit;
mAvailableSpaceRect.bottom = heightLimit;
super.setTextSize(
TypedValue.COMPLEX_UNIT_PX,
efficientTextSizeSearch(startSize, (int) mMaxTextSize,
mSizeTester, mAvailableSpaceRect));
}
private final SizeTester mSizeTester = new SizeTester() {
@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
@Override
public int onTestSize(int suggestedSize, RectF availableSPace) {
mPaint.setTextSize(suggestedSize);
String text = getText().toString();
boolean singleline = getMaxLines() == 1;
if (singleline) {
mTextRect.bottom = mPaint.getFontSpacing();
mTextRect.right = mPaint.measureText(text);
} else {
StaticLayout layout = new StaticLayout(text, mPaint,
mWidthLimit, Alignment.ALIGN_NORMAL, mSpacingMult,
mSpacingAdd, true);
// return early if we have more lines
if (getMaxLines() != NO_LINE_LIMIT
&& layout.getLineCount() > getMaxLines()) {
return 1;
}
mTextRect.bottom = layout.getHeight();
int maxWidth = -1;
for (int i = 0; i < layout.getLineCount(); i++) {
if (maxWidth < layout.getLineWidth(i)) {
maxWidth = (int) layout.getLineWidth(i);
}
}
mTextRect.right = maxWidth;
}
mTextRect.offsetTo(0, 0);
if (availableSPace.contains(mTextRect)) {
// may be too small, don't worry we will find the best match
return -1;
} else {
// too big
return 1;
}
}
};
/**
* Enables or disables size caching, enabling it will improve performance
* where you are animating a value inside TextView. This stores the font
* size against getText().length() Be careful though while enabling it as 0
* takes more space than 1 on some fonts and so on.
*
* @param enable
* enable font size caching
*/
public void enableSizeCache(boolean enable) {
mEnableSizeCache = enable;
mTextCachedSizes.clear();
adjustTextSize(getText().toString());
}
private int efficientTextSizeSearch(int start, int end,
SizeTester sizeTester, RectF availableSpace) {
if (!mEnableSizeCache) {
return binarySearch(start, end, sizeTester, availableSpace);
}
String text = getText().toString();
int key = text == null ? 0 : text.length();
int size = mTextCachedSizes.get(key);
if (size != 0) {
return size;
}
size = binarySearch(start, end, sizeTester, availableSpace);
mTextCachedSizes.put(key, size);
return size;
}
private static int binarySearch(int start, int end, SizeTester sizeTester,
RectF availableSpace) {
int lastBest = start;
int lo = start;
int hi = end - 1;
int mid = 0;
while (lo <= hi) {
mid = (lo + hi) >>> 1;
int midValCmp = sizeTester.onTestSize(mid, availableSpace);
if (midValCmp < 0) {
lastBest = lo;
lo = mid + 1;
} else if (midValCmp > 0) {
hi = mid - 1;
lastBest = hi;
} else {
return mid;
}
}
// make sure to return last best
// this is what should always be returned
return lastBest;
}
@Override
protected void onTextChanged(final CharSequence text, final int start,
final int before, final int after) {
super.onTextChanged(text, start, before, after);
reAdjust();
}
@Override
protected void onSizeChanged(int width, int height, int oldwidth,
int oldheight) {
mTextCachedSizes.clear();
super.onSizeChanged(width, height, oldwidth, oldheight);
if (width != oldwidth || height != oldheight) {
reAdjust();
}
}
}
Then, paste this code below the package line in your MainActivity class.
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.Random;
public class MainActivity extends Activity {
TextView textView;
Button button;
int songsSize;
ArrayList<String[]> songs = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
songs.add(new String[]{"Row row row your boat", "Gently down the stream", "Merrily merrily merrily", "Life is but a dream"});
songs.add(new String[]{"Ring-a-round the rosie", "Pockets full of posies", "Ashes! Ashes!", "We all fall down"});
songs.add(new String[]{"Twinkle twinkle little star", "How I wonder what you are", "Up above the world you fly", "Like a diamond in the sky"});
songs.add(new String[]{"Humpty Dumpty sat on a wall", "Humpty Dumpty had a great fall", "All the king's horses and all the king's men", "Couldn't put Humpty together again"});
songs.add(new String[]{"Baa baa black sheep", "Have you any wool?", "Yes, sir, yes, sir", "Three bags full"});
songs.add(new String[]{"London Bridge is falling down", "Falling down, falling down", "London Bridge is falling down", "My fair lady"});
//Replace the above songs with whatever songs you want,
//splitting the lines of the songs with commas
songsSize = songs.size();
textView = (AutoResizeTextView)findViewById(R.id.textview);
button = (Button)findViewById(R.id.button);
//button.setTextSize(textView.getTextSize());
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
changeSong();
}
});
}
String getSongFromArray(String[] song){
String textViewText = "";
for(int i=0; i<song.length-1; i++){
textViewText = textViewText + song[i] + System.getProperty ("line.separator");
}
return textViewText + song[song.length-1];
}
void changeSong(){
String[] song = songs.get(new Random().nextInt(songsSize));
String songText = getSongFromArray(song);
if(textView.getText().toString().equals(songText)) {
changeSong();
} else{
textView.setText(songText);
textView.setLines(song.length);
textView.setMaxLines(song.length);
textView.setTextSize(1000);
//button.setTextSize(textView.getTextSize());
}
}
}
Replace the songs in the MainActivity class with your own songs, separating the lyrics' lines with commas. In the XML file, replace the "Row, row, row your boat" text with the song that will appear first and change maxLines to the number of lines in that song.
