android - 在textview android上捏缩放

Question

你好朋友我已经完成了捏缩放文本视图并且它的工作正常但是问题是当我缩小文本视图位置改变并且我希望在放大和缩小期间固定文本视图的位置这是我的代码

public class MainActivity extends Activity {

    TextView scaleGesture;
    ScaleGestureDetector scaleGestureDetector;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        scaleGesture = (TextView)findViewById(R.id.article);
        scaleGesture.setText("this is some text");
        scaleGestureDetector = new ScaleGestureDetector(this, new simpleOnScaleGestureListener());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }


    @Override
    public boolean onTouchEvent(MotionEvent event) {
        // TODO Auto-generated method stub
        scaleGestureDetector.onTouchEvent(event);
        return true;
    }

    public class simpleOnScaleGestureListener extends
            SimpleOnScaleGestureListener {

        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            // TODO Auto-generated method stub
            float size = scaleGesture.getTextSize();
            Log.d("TextSizeStart", String.valueOf(size));

            float factor = detector.getScaleFactor();
            Log.d("Factor", String.valueOf(factor));


            float product = size*factor;
            Log.d("TextSize", String.valueOf(product));
            scaleGesture.setTextSize(TypedValue.COMPLEX_UNIT_PX, product);

            size = scaleGesture.getTextSize();
            Log.d("TextSizeEnd", String.valueOf(size));
            return true;
        }
    }
}

score 19 · Accepted Answer

我已经这样做了：

活动主.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/mytv"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="This is my sample text for pinch zoom demo, you can zoom in and out using pinch zoom, thanks" />

</RelativeLayout>

MainActivity.java：

import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.TextView;

public class MyTextViewPinchZoomClass extends Activity implements OnTouchListener {

    final static float STEP = 200;
    TextView mytv;
    float mRatio = 1.0f;
    int mBaseDist;
    float mBaseRatio;
    float fontsize = 13;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mytv = (TextView) findViewById(R.id.mytv);
        mytv.setTextSize(mRatio + 13);
    }

    public boolean onTouchEvent(MotionEvent event) {
        if (event.getPointerCount() == 2) {
            int action = event.getAction();
            int pureaction = action & MotionEvent.ACTION_MASK;
            if (pureaction == MotionEvent.ACTION_POINTER_DOWN) {
                mBaseDist = getDistance(event);
                mBaseRatio = mRatio;
            } else {
                float delta = (getDistance(event) - mBaseDist) / STEP;
                float multi = (float) Math.pow(2, delta);
                mRatio = Math.min(1024.0f, Math.max(0.1f, mBaseRatio * multi));
                mytv.setTextSize(mRatio + 13);
            }
        }
        return true;
    }

    int getDistance(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));
    }

    public boolean onTouch(View v, MotionEvent event) {
        return false;
    }
}

完毕

score 10 · Accepted Answer

public class MainActivity extends Activity {

TextView scaleGesture;
ScaleGestureDetector scaleGestureDetector;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    scaleGesture = (TextView)findViewById(R.id.article);
    scaleGesture.setText("this is some text");
    scaleGestureDetector = new ScaleGestureDetector(this, new simpleOnScaleGestureListener());
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}


@Override
public boolean onTouchEvent(MotionEvent event) {
    // TODO Auto-generated method stub
    scaleGestureDetector.onTouchEvent(event);
    return true;
}

public class simpleOnScaleGestureListener extends
        SimpleOnScaleGestureListener {

    @Override
    public boolean onScale(ScaleGestureDetector detector) {
        // TODO Auto-generated method stub
        float size = scaleGesture.getTextSize();
        Log.d("TextSizeStart", String.valueOf(size));

        float factor = detector.getScaleFactor();
        Log.d("Factor", String.valueOf(factor));


        float product = size*factor;
        Log.d("TextSize", String.valueOf(product));
        scaleGesture.setTextSize(TypedValue.COMPLEX_UNIT_PX, product);

        size = scaleGesture.getTextSize();
        Log.d("TextSizeEnd", String.valueOf(size));
        return true;
    }
}
 }

看法

<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=".MainActivity" >
<TextView
    android:id="@+id/article"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

score 0 · Accepted Answer

请使用以下代码：

public class TouchExampleView extends View {

private static final int INVALID_POINTER_ID = -1;

private Drawable mIcon;
private float mPosX;
private float mPosY;

private float mLastTouchX;
private float mLastTouchY;
private int mActivePointerId = INVALID_POINTER_ID;

private ScaleGestureDetector mScaleDetector;
private float mScaleFactor = 1.f;

public TouchExampleView(Context context) {
    this(context, null, 0);
}

public TouchExampleView(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
}

public TouchExampleView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    mIcon = context.getResources().getDrawable(R.drawable.toggle);
    mIcon.setBounds(0, 0, mIcon.getIntrinsicWidth(),
            mIcon.getIntrinsicHeight());

    mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
}

@Override
public boolean onTouchEvent(MotionEvent ev) {
    // Let the ScaleGestureDetector inspect all events.
    mScaleDetector.onTouchEvent(ev);

    final int action = ev.getAction();
    switch (action & MotionEvent.ACTION_MASK) {
    case MotionEvent.ACTION_DOWN: {
        final float x = ev.getX();
        final float y = ev.getY();

        mLastTouchX = x;
        mLastTouchY = y;
        mActivePointerId = ev.getPointerId(0);
        break;
    }

    case MotionEvent.ACTION_MOVE: {
        final int pointerIndex = ev.findPointerIndex(mActivePointerId);
        final float x = ev.getX(pointerIndex);
        final float y = ev.getY(pointerIndex);

        // Only move if the ScaleGestureDetector isn't processing a gesture.
        if (!mScaleDetector.isInProgress()) {
            final float dx = x - mLastTouchX;
            final float dy = y - mLastTouchY;

            mPosX += dx;
            mPosY += dy;

            invalidate();
        }

        mLastTouchX = x;
        mLastTouchY = y;

        break;
    }

    case MotionEvent.ACTION_UP: {
        mActivePointerId = INVALID_POINTER_ID;
        break;
    }

    case MotionEvent.ACTION_CANCEL: {
        mActivePointerId = INVALID_POINTER_ID;
        break;
    }

    case MotionEvent.ACTION_POINTER_UP: {
        final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
        final int pointerId = ev.getPointerId(pointerIndex);
        if (pointerId == mActivePointerId) {
            // This was our active pointer going up. Choose a new
            // active pointer and adjust accordingly.
            final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
            mLastTouchX = ev.getX(newPointerIndex);
            mLastTouchY = ev.getY(newPointerIndex);
            mActivePointerId = ev.getPointerId(newPointerIndex);
        }
        break;
    }
    }

    return true;
}

@Override
public void onDraw(Canvas canvas) {
    super.onDraw(canvas);

    canvas.save();
    canvas.translate(mPosX, mPosY);
    canvas.scale(mScaleFactor, mScaleFactor);
    Paint paint = new Paint(); 
    paint.setStyle(Style.FILL);  
    paint.setColor(Color.BLACK); 
    paint.setTextSize(20); 
    canvas.drawText("Hello how are you", mPosX, mPosY, paint);
    mIcon.draw(canvas);
    canvas.restore();
}

private class ScaleListener extends
        ScaleGestureDetector.SimpleOnScaleGestureListener {
    @Override
    public boolean onScale(ScaleGestureDetector detector) {
        mScaleFactor *= detector.getScaleFactor();

        // Don't let the object get too small or too large.
        mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 5.0f));

        invalidate();
        return true;
    }
}

}

android - 在textview android上捏缩放

3 回答 3

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