How to enlarge text in Android?

Question

Can someone guide me to do zoom and zoom operations across multiple views in android? I need to perform zoom and output operations when touching an image, text representations. What should be my parent layout? Here is the code to enlarge the image when you click on the image. How to zoom text? Please help me.

// These matrices will be used to scale points of the image Matrix matrix = new Matrix(); Matrix savedMatrix = new Matrix(); // The 3 states (events) which the user is trying to perform static final int NONE = 0; static final int DRAG = 1; static final int ZOOM = 2; int mode = NONE; // these PointF objects are used to record the point(s) the user is touching PointF start = new PointF(); PointF mid = new PointF(); float oldDist = 1f; private void zoom(View v, MotionEvent event) { ImageView view = (ImageView) v; view.setScaleType(ImageView.ScaleType.MATRIX); float scale; // dumpEvent(event); // Handle touch events here... switch (event.getAction() & MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_DOWN: // first finger down only savedMatrix.set(matrix); start.set(event.getX(), event.getY()); mode = DRAG; break; case MotionEvent.ACTION_UP: // first finger lifted case MotionEvent.ACTION_POINTER_UP: // second finger lifted mode = NONE; break; case MotionEvent.ACTION_POINTER_DOWN: // first and second finger down oldDist = spacing(event); if (oldDist > 5f) { savedMatrix.set(matrix); midPoint(mid, event); mode = ZOOM; } break; case MotionEvent.ACTION_MOVE: if (mode == DRAG) { matrix.set(savedMatrix); matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); // create the transformation in the matrix of points } else if (mode == ZOOM) { // pinch zooming float newDist = spacing(event); if (newDist > 5f) { matrix.set(savedMatrix); scale = newDist / oldDist; // setting the scaling of the // matrix...if scale > 1 means // zoom in...if scale < 1 means // zoom out matrix.postScale(scale, scale, mid.x, mid.y); } } break; } view.setImageMatrix(matrix); // display the transformation on screen } /* * -------------------------------------------------------------------------- * Method: spacing Parameters: MotionEvent Returns: float Description: * * checks the spacing between the two fingers on touch * ---------------------------------------------------- */ private float spacing(MotionEvent event) { float x = event.getX(0) - event.getX(1); float y = event.getY(0) - event.getY(1); return FloatMath.sqrt(x * x + y * y); } /* * -------------------------------------------------------------------------- * Method: midPoint Parameters: PointF object, MotionEvent Returns: void * Description: calculates the midpoint between the two fingers * ------------------------------------------------------------ */ private void midPoint(PointF point, MotionEvent event) { float x = event.getX(0) + event.getX(1); float y = event.getY(0) + event.getY(1); point.set(x / 2, y / 2); } 

Answer 1

To enlarge the text, you can use the same code that you need to enlarge the image. But you have to change the textview to an image, and then perform the zoom operations. Here is the link to convert textview to imageview Convert TextView-> Bitmap-> ImageView and nothing is displayed

Answer 2

The above but you to it as shown below:

In oncreate (), you must initialize your text view and set the ontouch event on it, as shown below

 TextView tv = (TextView)findViewById(R.id.name); tv.setText("text"); tv.setOnTouchListener(this); 

here is the complete code including your code:

 public class MyTextView extends Activity implements OnTouchListener{ private static final String TAG = "Touch"; @SuppressWarnings("unused") private static final float MIN_ZOOM = 1f,MAX_ZOOM = 1f; // These matrices will be used to scale points of the image Matrix matrix = new Matrix(); Matrix savedMatrix = new Matrix(); // The 3 states (events) which the user is trying to perform static final int NONE = 0; static final int DRAG = 1; static final int ZOOM = 2; int mode = NONE; // these PointF objects are used to record the point(s) the user is touching PointF start = new PointF(); PointF mid = new PointF(); float oldDist = 1f; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); TextView iv = new TextView(this); iv.setText("text"); iv.setOnTouchListener(this); setContentView(iv); } @Override public boolean onTouch(View v, MotionEvent event) { // TODO Auto-generated method stub ImageView view = (ImageView) v; view.setScaleType(ImageView.ScaleType.MATRIX); float scale; dumpEvent(event); // Handle touch events here... switch (event.getAction() & 255) { case MotionEvent.ACTION_DOWN: // first finger down only savedMatrix.set(matrix); start.set(event.getX(), event.getY()); Log.d(TAG, "mode=DRAG"); // write to LogCat mode = DRAG; break; case MotionEvent.ACTION_UP: // first finger lifted case 6: // second finger lifted mode = NONE; Log.d(TAG, "mode=NONE"); break; case 5: // first and second finger down oldDist = spacing(event); Log.d(TAG, "oldDist=" + oldDist); if (oldDist > 5f) { savedMatrix.set(matrix); midPoint(mid, event); mode = ZOOM; Log.d(TAG, "mode=ZOOM"); } break; case MotionEvent.ACTION_MOVE: if (mode == DRAG) { matrix.set(savedMatrix); matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); // create the transformation in the matrix of points } else if (mode == ZOOM) { // pinch zooming float newDist = spacing(event); Log.d(TAG, "newDist=" + newDist); if (newDist > 5f) { matrix.set(savedMatrix); scale = newDist / oldDist; // setting the scaling of the // matrix...if scale > 1 means // zoom in...if scale < 1 means // zoom out matrix.postScale(scale, scale, mid.x, mid.y); } } break; } view.setImageMatrix(matrix); // display the transformation on screen return true; // indicate event was handled } private float spacing(MotionEvent event) { float x = event.getX(0) - event.getX(1); float y = event.getY(0) - event.getY(1); return FloatMath.sqrt(x * x + y * y); } /* * -------------------------------------------------------------------------- * Method: midPoint Parameters: PointF object, MotionEvent Returns: void * Description: calculates the midpoint between the two fingers * ------------------------------------------------------------ */ private void midPoint(PointF point, MotionEvent event) { float x = event.getX(0) + event.getX(1); float y = event.getY(0) + event.getY(1); point.set(x / 2, y / 2); } /** Show an event in the LogCat view, for debugging */ private void dumpEvent(MotionEvent event) { String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE","POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" }; StringBuilder sb = new StringBuilder(); int action = event.getAction(); int actionCode = action & MotionEvent.ACTION_MASK; sb.append("event ACTION_").append(names[actionCode]); if (actionCode == MotionEvent.ACTION_POINTER_DOWN || actionCode == MotionEvent.ACTION_POINTER_UP) { sb.append("(pid ").append(action >> MotionEvent.ACTION_POINTER_ID_SHIFT); sb.append(")"); } sb.append("["); for (int i = 0; i < event.getPointerCount(); i++) { sb.append("#").append(i); sb.append("(pid ").append(event.getPointerId(i)); sb.append(")=").append((int) event.getX(i)); sb.append(",").append((int) event.getY(i)); if (i + 1 < event.getPointerCount()) sb.append(";"); } sb.append("]"); Log.d("Touch Events ---------", sb.toString()); } } 

Answer 3

I found a very simple solution to implement zoom in / out in a text view. Maybe this helps someone

 package com.app; import android.os.Bundle; import android.util.TypedValue; import android.view.MotionEvent; import android.widget.TextView; import android.support.v7.app.AppCompatActivity; import android.view.View; public class MyActivity extends AppCompatActivity implements View.OnTouchListener{ public static final int TEXT_MAX_SIZE = 140; public static final int TEXT_MIN_SIZE = 40; private static final int STEP = 4; private int mBaseDistZoomIn; private int mBaseDistZoomOut; protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.my_activity); . . . TextView viewById = (TextView) findViewById(R.id.some_text_view); viewById.setOnTouchListener(this); } @Override public boolean onTouch(View v, MotionEvent event) { if (event.getPointerCount() == 2) { TextView viewById = (TextView) findViewById(R.id.some_text_view); int action = event.getAction(); int pure = action & MotionEvent.ACTION_MASK; if (pure == MotionEvent.ACTION_POINTER_DOWN && viewById.getTextSize() <= TEXT_MAX_SIZE && viewById.getTextSize() >= TEXT_MIN_SIZE) { mBaseDistZoomIn = getDistanceFromEvent(event); mBaseDistZoomOut = getDistanceFromEvent(event); } else { int currentDistance = getDistanceFromEvent(event); if (currentDistance > mBaseDistZoomIn) { float finalSize = viewById.getTextSize() + STEP; if (finalSize > TEXT_MAX_SIZE) { finalSize = TEXT_MAX_SIZE; } viewById.setTextSize(TypedValue.COMPLEX_UNIT_PX, finalSize); } else { if (currentDistance < mBaseDistZoomOut) { float finalSize = viewById.getTextSize() - STEP; if (finalSize < TEXT_MIN_SIZE) { finalSize = TEXT_MIN_SIZE; } viewById.setTextSize(TypedValue.COMPLEX_UNIT_PX, finalSize); } } } return true; } return false; } // good function to get the distance between the multiple touch int getDistanceFromEvent(MotionEvent event) { int dx = (int) (event.getX(0) - event.getX(1)); int dy = (int) (event.getY(0) - event.getY(1)); return (int) (Math.sqrt(dx * dx + dy * dy)); } } 

Answer 4

 first you should convert Textview to imageview.Next you should apply sample image view drag functionality. ----------------------------- TextView tv = new TextView(this); FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams( FrameLayout.LayoutParams.FILL_PARENT, FrameLayout.LayoutParams.FILL_PARENT); tv.setLayoutParams(layoutParams); tv.setText("Text"); tv.setTextColor(Color.BLACK); tv.setBackgroundColor(Color.TRANSPARENT); Bitmap testB; testB = Bitmap.createBitmap(80, 100, Bitmap.Config.ARGB_8888); Canvas c = new Canvas(testB); tv.layout(30, 40, 200, 100); tv.draw(c); ImageView iv = (ImageView) findViewById(R.id.imageView); iv.setLayoutParams(layoutParams); iv.setBackgroundColor(Color.GRAY);`enter code here` iv.setImageBitmap(testB); iv.setMaxHeight(80); iv.setMaxWidth(200); iv.setOnTouchListener(this);