I have an activity with LinearLayout as its main Layout. In that layout, there is a button that adds a View (R.layout.motor_block) to the main layout (R.id.layout):
LayoutInflater inflater =
(LayoutInflater)this.getSystemService( Context.LAYOUT_INFLATER_SERVICE );
View iv = inflater.inflate( R.layout.motor_block, null );
RelativeLayout rl = (RelativeLayout) findViewById(R.id.layout);
rl.addView(iv);
This works fine, but when I add more Views, the screen gets filled up with them so I need a way to "extend" the size by adding pan so I can go through all the views. I also want to add zoom.
I tried to use a WebView:
RelativeLayout rl = (RelativeLayout) findViewById(R.id.layout);
WebView wv = (WebView) findViewById(R.id.webView1);
wv.getSettings().setSupportZoom(true);
wv.getSettings().setBuiltInZoomControls(true);
wv.getSettings().setUseWideViewPort(true);
wv.getSettings().setLoadWithOverviewMode(true);
wv.getSettings().setDisplayZoomControls(false);
wv.getSettings().setDefaultZoom(WebSettings.ZoomDensity.FAR);
wv.addView(iv);
The Views get added to it, and pan works. The problem is that when I zoom, the webView zooms the background, and the Views don't change size.
I also tried some custom views but they didn't support views with child views.
What is the best way to accomplish this?
Just an example. Use setTranslationX/Y and setScaleX/Y on the main container view. Its children will scale and translate with it.
public class MainActivity extends Activity {
private RelativeLayout mainLayout;
private ScaleGestureDetector scaleGestureDetector;
private float scale = 1;
private PointF touchPoint;
private PointF pan;
private boolean isScaling;
private boolean endScalingNextUp;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainLayout = (RelativeLayout) findViewById(id.main_layout);
scaleGestureDetector = new ScaleGestureDetector(this, new ExampleScaleGestureListener());
Button b = ((Button) findViewById(id.btn_reset));
b.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
reset();
}
});
reset();
}
@Override
public boolean onTouchEvent(MotionEvent event) {
scaleGestureDetector.onTouchEvent(event);
if (scale != 1 && !isScaling) {
float x = event.getRawX();
float y = event.getRawY();
if (event.getAction() == MotionEvent.ACTION_DOWN) {
touchPoint = new PointF(x, y);
} else if (event.getAction() == MotionEvent.ACTION_MOVE && touchPoint != null) {
pan.x = x - touchPoint.x;
pan.y = y - touchPoint.y;
panView();
}
}
if (isScaling && endScalingNextUp) {
if (event.getAction() == MotionEvent.ACTION_POINTER_UP) {
endScalingNextUp = false;
isScaling = false;
}
}
return true;
}
private void setPivot(float focusX, float focusY) {
mainLayout.setPivotX(focusX);
mainLayout.setPivotY(focusY);
}
private void scaleView() {
mainLayout.setScaleX(scale);
mainLayout.setScaleY(scale);
}
private void panView() {
mainLayout.setTranslationX(pan.x);
mainLayout.setTranslationY(pan.y);
}
private void reset() {
setPivot(0, 0);
scale = 1;
scaleView();
pan = new PointF(0, 0);
panView();
isScaling = false;
}
private class ExampleScaleGestureListener implements OnScaleGestureListener {
private static final float SCALE_SPEED = .02f;
@Override
public void onScaleEnd(ScaleGestureDetector detector) {
endScalingNextUp = true;
}
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
float focusX = detector.getFocusX();
float focusY = detector.getFocusY();
setPivot(focusX, focusY);
isScaling = true;
endScalingNextUp = false;
return true;
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
isScaling = true;
endScalingNextUp = false;
if (detector.getScaleFactor() < 1) {
scale -= SCALE_SPEED;
} else if (detector.getScaleFactor() > 1) {
scale += SCALE_SPEED;
}
scaleView();
return true;
}
}
}
<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"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:id="@+id/main_layout"
tools:context=".MainActivity" >
<TextView
android:id="@+id/tv"
android:layout_centerInParent="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/tv"
android:layout_marginBottom="69dp"
android:layout_marginRight="29dp"
android:layout_toLeftOf="@+id/tv"
android:src="@drawable/ic_launcher" />
<Button
android:id="@+id/btn_reset"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/tv"
android:layout_centerHorizontal="true"
android:layout_marginTop="22dp"
android:text="Reset" />
</RelativeLayout>
The most easy way is to add all these views in a ScrollView. You can then add the ScrollView into a HorizontalScrollView to have scroll in both direction. Have a Gesture for pinch and zoom gestures and call listeners for them. For zoom you can increase the size of each view via running a loop or probably use ScaleGestureDetector.
This method is a little choppy, but works. Check the following answer for more info -
Implementing Pan and Zoom
Update:-
Here're some more SO answers -
How to implement zoom effect for image view in android?
android pinch zoom
来源：https://stackoverflow.com/questions/20225265/pinch-zoom-and-pan