放大图片onclick android

Question

您好我正在尝试开发一个Android应用程序，但我卡住了，请帮助我 我试图在点击时放大图像，以便用户点击图像可以看到完整的图像。我设法写了一些代码，但它没有工作

我的java类是

import android.app.Activity;
import android.content.Intent;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.os.Bundle;
import android.os.Handler;
import android.util.FloatMath;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

public class quiz extends Activity {

    boolean imageTouch = false;
    Matrix matrix = new Matrix();
    Matrix savedMatrix = new Matrix();
    PointF start = new PointF();
    PointF mid = new PointF();
    float oldDist = 1f;


    static final int NONE = 0;
    static final int DRAG = 1;
    static final int ZOOM = 2;

    int mode = NONE;

    public GestureDetector mDetector;

    @
    Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.quiz);

        ImageView imgp = (ImageView) findViewById(R.id.imageView1);


        imgp.setOnTouchListener(new View.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:
                        v.performClick();
                        break;

                    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;
            }
            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);
            }
        });


    }
}