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Add drag/drop demo to ApiDemos

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Drag/drop among four big dots on screen.  Drags to a dot will have
the identity of the originating dot put into a text field below the dots.
In all cases, a text field to the right of the dots reports whether the
drag ended in a successful drop.

Attempting to start a drag from a dot reading "Drag ANR" should ANR and
be cleaned up properly.

Attempting to drop onto a dot reading "Drop ANR" should similarly ANR
and be cleaned up properly.

Drags from a dot labelled "Local" are restricted to targets within
the app's own window -- they are not draggable to the system "shirt
pocket" drop target, etc.

A drop onto the same dot that it originated from will append text to
that effect to the message that notes the dropped payload.  This
uses the "local state" convenience mechanism in startDrag() and
DragEvent.getLocalState().

Change-Id: Ic5cd6a29186a84c91d3dc4187e83e7bcf530ba2f
This commit is contained in:
Christopher Tate
2010-12-01 16:46:28 -08:00
parent 4799e5583e
commit 8f2e8f48b9
6 changed files with 445 additions and 0 deletions
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58
samples/ApiDemos/src/com/example/android/apis/view/DragAndDropDemo.java Normal file
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/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.apis.view;
import com.example.android.apis.R;
import android.app.Activity;
import android.os.Bundle;
import android.view.DragEvent;
import android.view.View;
import android.widget.TextView;
public class DragAndDropDemo extends Activity {
TextView mResultText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.drag_layout);
TextView text = (TextView) findViewById(R.id.drag_text);
DraggableDot dot = (DraggableDot) findViewById(R.id.drag_dot_1);
dot.setReportView(text);
dot = (DraggableDot) findViewById(R.id.drag_dot_2);
dot.setReportView(text);
dot = (DraggableDot) findViewById(R.id.drag_dot_3);
dot.setReportView(text);
dot = (DraggableDot) findViewById(R.id.drag_dot_4);
dot.setReportView(text);
mResultText = (TextView) findViewById(R.id.drag_result_text);
mResultText.setOnDragListener(new View.OnDragListener() {
@Override
public boolean onDrag(View v, DragEvent event) {
final int action = event.getAction();
if (action == DragEvent.ACTION_DRAG_ENDED) {
final boolean dropped = event.getResult();
mResultText.setText(dropped ? "Dropped!" : "No drop");
}
return false;
}
});
}
}

266
samples/ApiDemos/src/com/example/android/apis/view/DraggableDot.java Normal file
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/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.apis.view;
import com.example.android.apis.R;
import android.content.ClipData;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.*;
import android.os.SystemClock;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.util.Log;
import android.view.DragEvent;
import android.view.View;
import android.widget.TextView;
public class DraggableDot extends View {
static final String TAG = "DraggableDot";
private boolean mDragInProgress;
private boolean mHovering;
private boolean mAcceptsDrag;
TextView mReportView;
private Paint mPaint;
private TextPaint mLegendPaint;
private Paint mGlow;
private static final int NUM_GLOW_STEPS = 10;
private static final int GREEN_STEP = 0x0000FF00 / NUM_GLOW_STEPS;
private static final int WHITE_STEP = 0x00FFFFFF / NUM_GLOW_STEPS;
private static final int ALPHA_STEP = 0xFF000000 / NUM_GLOW_STEPS;
int mRadius;
int mAnrType;
boolean mLocalOnly;
CharSequence mLegend;
static final int ANR_NONE = 0;
static final int ANR_THUMBNAIL = 1;
static final int ANR_DROP = 2;
void sleepSixSeconds() {
// hang forever; good for producing ANRs
long start = SystemClock.uptimeMillis();
do {
try { Thread.sleep(1000); } catch (InterruptedException e) {}
} while (SystemClock.uptimeMillis() < start + 6000);
}
// Thumbnail builder that can ANR if desired
class ANRThumbBuilder extends DragThumbnailBuilder {
boolean mDoAnr;
public ANRThumbBuilder(View view, boolean doAnr) {
super(view);
mDoAnr = doAnr;
}
@Override
public void onDrawThumbnail(Canvas canvas) {
if (mDoAnr) {
sleepSixSeconds();
}
super.onDrawThumbnail(canvas);
}
}
public DraggableDot(Context context, AttributeSet attrs) {
super(context, attrs);
setFocusable(true);
setClickable(true);
mLegend = "";
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setStrokeWidth(6);
mPaint.setColor(0xFFD00000);
mLegendPaint = new TextPaint();
mLegendPaint.setAntiAlias(true);
mLegendPaint.setTextAlign(Paint.Align.CENTER);
mLegendPaint.setColor(0xFFF0F0FF);
mGlow = new Paint();
mGlow.setAntiAlias(true);
mGlow.setStrokeWidth(1);
mGlow.setStyle(Paint.Style.STROKE);
// look up any layout-defined attributes
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.DraggableDot);
final int N = a.getIndexCount();
for (int i = 0; i < N; i++) {
int attr = a.getIndex(i);
switch (attr) {
case R.styleable.DraggableDot_radius: {
mRadius = a.getDimensionPixelSize(attr, 0);
} break;
case R.styleable.DraggableDot_legend: {
mLegend = a.getText(attr);
} break;
case R.styleable.DraggableDot_anr: {
mAnrType = a.getInt(attr, 0);
} break;
case R.styleable.DraggableDot_localOnly: {
mLocalOnly = a.getBoolean(attr, false);
} break;
}
}
Log.i(TAG, "DraggableDot @ " + this + " : radius=" + mRadius + " legend='" + mLegend
+ "' anr=" + mAnrType + " local=" + mLocalOnly);
setOnLongClickListener(new View.OnLongClickListener() {
public boolean onLongClick(View v) {
ClipData data = ClipData.newPlainText("dot", null, "Dot : " + v.toString());
v.startDrag(data, new ANRThumbBuilder(v, mAnrType == ANR_THUMBNAIL),
mLocalOnly, (Object)v);
return true;
}
});
}
void setReportView(TextView view) {
mReportView = view;
}
@Override
protected void onDraw(Canvas canvas) {
float wf = getWidth();
float hf = getHeight();
final float cx = wf/2;
final float cy = hf/2;
wf -= getPaddingLeft() + getPaddingRight();
hf -= getPaddingTop() + getPaddingBottom();
float rad = (wf < hf) ? wf/2 : hf/2;
canvas.drawCircle(cx, cy, rad, mPaint);
if (mLegend != null && mLegend.length() > 0) {
canvas.drawText(mLegend, 0, mLegend.length(),
cx, cy + mLegendPaint.getFontSpacing()/2,
mLegendPaint);
}
// if we're in the middle of a drag, light up as a potential target
if (mDragInProgress && mAcceptsDrag) {
for (int i = NUM_GLOW_STEPS; i > 0; i--) {
int color = (mHovering) ? WHITE_STEP : GREEN_STEP;
color = i*(color | ALPHA_STEP);
mGlow.setColor(color);
canvas.drawCircle(cx, cy, rad, mGlow);
rad -= 0.5f;
canvas.drawCircle(cx, cy, rad, mGlow);
rad -= 0.5f;
}
}
}
@Override
protected void onMeasure(int widthSpec, int heightSpec) {
int totalDiameter = 2*mRadius + getPaddingLeft() + getPaddingRight();
setMeasuredDimension(totalDiameter, totalDiameter);
}
/**
* Drag and drop
*/
@Override
public boolean onDragEvent(DragEvent event) {
boolean result = false;
switch (event.getAction()) {
case DragEvent.ACTION_DRAG_STARTED: {
// claim to accept any dragged content
Log.i(TAG, "Drag started, event=" + event);
// cache whether we accept the drag to return for LOCATION events
mDragInProgress = true;
mAcceptsDrag = result = true;
// Redraw in the new visual state if we are a potential drop target
if (mAcceptsDrag) {
invalidate();
}
} break;
case DragEvent.ACTION_DRAG_ENDED: {
Log.i(TAG, "Drag ended.");
if (mAcceptsDrag) {
invalidate();
}
mDragInProgress = false;
mHovering = false;
} break;
case DragEvent.ACTION_DRAG_LOCATION: {
// we returned true to DRAG_STARTED, so return true here
Log.i(TAG, "... seeing drag locations ...");
result = mAcceptsDrag;
} break;
case DragEvent.ACTION_DROP: {
Log.i(TAG, "Got a drop! dot=" + this + " event=" + event);
if (mAnrType == ANR_DROP) {
sleepSixSeconds();
}
processDrop(event);
result = true;
} break;
case DragEvent.ACTION_DRAG_ENTERED: {
Log.i(TAG, "Entered dot @ " + this);
mHovering = true;
invalidate();
} break;
case DragEvent.ACTION_DRAG_EXITED: {
Log.i(TAG, "Exited dot @ " + this);
mHovering = false;
invalidate();
} break;
default:
Log.i(TAG, "other drag event: " + event);
result = mAcceptsDrag;
break;
}
return result;
}
private void processDrop(DragEvent event) {
final ClipData data = event.getClipData();
final int N = data.getItemCount();
for (int i = 0; i < N; i++) {
ClipData.Item item = data.getItem(i);
Log.i(TAG, "Dropped item " + i + " : " + item);
if (mReportView != null) {
String text = item.coerceToText(getContext()).toString();
if (event.getLocalState() == (Object) this) {
text += " : Dropped on self!";
}
mReportView.setText(text);
}
}
}
}