ImageVIew Zoom 在android中不起作用

Question

我在android中为imageView缩放做了一个简单的演示程序..我尝试了以下代码，但是当捏或点击时图像不会缩放..请帮助

ma​​in.java

package com.example.imageviewzoomdemo;

import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.FloatMath;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;

public class MainActivity extends Activity {
ImageView imageview;

Matrix matrix =new Matrix();
Matrix savedMatrix =new Matrix();
PointF start = new PointF();
PointF mid =new PointF();
float  oldDist = 1f;
final static int NONE = 0;
final static int DRAG = 1;
final static int ZOOM = 2;
int mode = NONE;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageview=(ImageView)findViewById(R.id.imageView1);

        imageview.setOnTouchListener(new OnTouchListener() {

            @Override
            public boolean onTouch(View v, MotionEvent event) {
                ImageView view =(ImageView)v;
                System.out.println("matrix=" + savedMatrix.toString());
                switch (event.getAction() & MotionEvent.ACTION_MASK) {
                case MotionEvent.ACTION_DOWN:

                    savedMatrix.set(matrix);
                    start.set(event.getX(), event.getY());
                    mode = DRAG;
                    break;

                case MotionEvent.ACTION_POINTER_DOWN:

                    oldDist = spacing(event);

                    if (oldDist > 10f) {
                        savedMatrix.set(matrix);
                        midPoint(mid, event);
                        mode = ZOOM;
                    }
                    break;

                case MotionEvent.ACTION_UP:

                case MotionEvent.ACTION_POINTER_UP:
                    mode = NONE;

                    break;

                case MotionEvent.ACTION_MOVE:
                    if (mode == DRAG) {
                        matrix.set(savedMatrix);
                        matrix.postTranslate(event.getX() - start.x,
                                event.getY() - start.y);
                    } else if (mode == ZOOM) {
                        float newDist = spacing(event);
                        if (newDist > 10f) {
                            matrix.set(savedMatrix);
                            float scale = newDist / oldDist;
                            matrix.postScale(scale, scale, mid.x, mid.y);
                        }
                    }
                    break;

                }
                view.setImageMatrix(matrix);

                return true;
            }

            @SuppressLint("FloatMath")
            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);
            }

            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);
            }
        });

    }

}

我正在获取图像，但是当我单击该图像时它没有缩放。

Answer 1

这个对我有用。试试看。

    public class Touch implements OnTouchListener {

    // These matrices will be used to move and zoom image  
    Matrix matrix = new Matrix();  
    Matrix savedMatrix = new Matrix();  

    // We can be in one of these 3 states  
    static final int NONE = 0;
    static final int DRAG = 1;  
    static final int ZOOM = 2;  
    int mode = NONE;  

    // Remember some things for zooming  
    PointF start = new PointF();  
    PointF mid = new PointF();  
    float oldDist = 1f;

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        // TODO Auto-generated method stub

        ImageView view = (ImageView)v;
        view.setScaleType(ImageView.ScaleType.MATRIX);

        // Handle touch events here...
        switch (event.getAction() & MotionEvent.ACTION_MASK) {
        case MotionEvent.ACTION_DOWN:
            savedMatrix.set(matrix);
            start.set(event.getX(), event.getY());
            mode = DRAG;

            break;

        case MotionEvent.ACTION_POINTER_DOWN:  
            oldDist = spacing(event);  
            if (oldDist > 10f) {  
                savedMatrix.set(matrix);  
                midPoint(mid, event);  
                mode = ZOOM;  
            }  
            break;  

        case MotionEvent.ACTION_UP:  

        case MotionEvent.ACTION_POINTER_UP:  
            mode = NONE;  
            break;  


        case MotionEvent.ACTION_MOVE:

            if(mode == DRAG)
            {
                matrix.set(savedMatrix);  
                matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); 
            }

            else if(mode == ZOOM)
            {
                float newDist = spacing(event);  
                if (newDist > 10f) {  
                    matrix.set(savedMatrix);  
                    float scale = newDist / oldDist;  
                    matrix.postScale(scale, scale, mid.x, mid.y);  
                } 
            }
            break;
        }


        view.setImageMatrix(matrix);


        return true;
    }


    /** Determine the space between the first two fingers */  
    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);  
    }  

    /** Calculate the mid point of the first 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);  
    }  

}

就这样用吧

ImageView iv = (ImageView)findViewById(R.id.imageView1);
    iv.setOnTouchListener(new Touch());

Answer 2

你可以使用自定义的 imagview 控件.. 检查这个 https://github.com/kilaka/ImageViewZoom