这是实现图层概念的代码。即动态添加图层。我在//中覆盖了来自Drawable.callback的mcallback中的错误。 有人可以帮我解决它。它说mcallback无法解析为变量。 提前致谢
package com.cts.drawable;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.*;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.Drawable.Callback;
import android.util.AttributeSet;
import android.view.View;
import java.io.IOException;
/**
* A Drawable that manages an array of other Drawables. These are drawn in array
* order, so the element with the largest index will be drawn on top.
* <p>
* It can be defined in an XML file with the <code><layer-list> element.
* Each Drawable in the layer is defined in a nested <code><item>.
* </p>
*
* @attr ref android.R.styleable#LayerDrawableItem_left
* @attr ref android.R.styleable#LayerDrawableItem_top
* @attr ref android.R.styleable#LayerDrawableItem_right
* @attr ref android.R.styleable#LayerDrawableItem_bottom
* @attr ref android.R.styleable#LayerDrawableItem_drawable
* @attr ref android.R.styleable#LayerDrawableItem_id
*/
public class LayerDrawable extends Drawable implements Drawable.Callback {
LayerState mLayerState;
private int[] mPaddingL;
private int[] mPaddingT;
private int[] mPaddingR;
private int[] mPaddingB;
private final Rect mTmpRect = new Rect();
private boolean mMutated;
/**
* Create a new layer drawable with the list of specified layers.
*
* @param layers A list of drawables to use as layers in this new drawable.
*/
public LayerDrawable(Drawable[] layers) {
this(layers, null);
}
/**
* Create a new layer drawable with the specified list of layers and the specified
* constant state.
*
* @param layers The list of layers to add to this drawable.
* @param state The constant drawable state.
*/
LayerDrawable(Drawable[] layers, LayerState state) {
this(state, null);
int length = layers.length;
ChildDrawable[] r = new ChildDrawable[length];
for (int i = 0; i < length; i++) {
r[i] = new ChildDrawable();
r[i].mDrawable = layers[i];
layers[i].setCallback(this);
mLayerState.mChildrenChangingConfigurations |= layers [i].getChangingConfigurations();
}
mLayerState.mNum = length;
mLayerState.mChildren = r;
ensurePadding();
}
LayerDrawable() {
this((LayerState) null, null);
}
LayerDrawable(LayerState state, Resources res) {
LayerState as = createConstantState(state, res);
mLayerState = as;
if (as.mNum > 0) {
ensurePadding();
}
}
LayerState createConstantState(LayerState state, Resources res) {
return new LayerState(state, this, res);
}
@Override
public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs)
throws XmlPullParserException, IOException {
super.inflate(r, parser, attrs);
int type;
final int innerDepth = parser.getDepth() + 1;
int depth;
while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
&& ((depth = parser.getDepth()) >= innerDepth || type != XmlPullParser.END_TAG)) {
if (type != XmlPullParser.START_TAG) {
continue;
}
if (depth > innerDepth || !parser.getName().equals("item")) {
continue;
}
TypedArray a = r.obtainAttributes(attrs,
R.styleable.LayerDrawableItem);
int left = a.getDimensionPixelOffset(
R.styleable.LayerDrawableItem_LayerDrawableItem_left, 0);
int top = a.getDimensionPixelOffset(
R.styleable.LayerDrawableItem_LayerDrawableItem_top, 0);
int right = a.getDimensionPixelOffset(
R.styleable.LayerDrawableItem_LayerDrawableItem_right, 0);
int bottom = a.getDimensionPixelOffset(
R.styleable.LayerDrawableItem_LayerDrawableItem_bottom, 0);
int drawableRes = a.getResourceId(
R.styleable.LayerDrawableItem_LayerDrawableItem_drawable, 0);
int id = a.getResourceId(R.styleable.LayerDrawableItem_LayerDrawableItem_id,
View.NO_ID);
a.recycle();
Drawable dr;
if (drawableRes != 0) {
dr = r.getDrawable(drawableRes);
} else {
while ((type = parser.next()) == XmlPullParser.TEXT) {
}
if (type != XmlPullParser.START_TAG) {
throw new XmlPullParserException(parser.getPositionDescription()
+ ": <item> tag requires a 'drawable' attribute or "
+ "child tag defining a drawable");
}
dr = Drawable.createFromXmlInner(r, parser, attrs);
}
addLayer(dr, id, left, top, right, bottom);
}
ensurePadding();
onStateChange(getState());
}
/**
* Add a new layer to this drawable. The new layer is identified by an id.
*
* @param layer The drawable to add as a layer.
* @param id The id of the new layer.
* @param left The left padding of the new layer.
* @param top The top padding of the new layer.
* @param right The right padding of the new layer.
* @param bottom The bottom padding of the new layer.
*/
private void addLayer(Drawable layer, int id, int left, int top, int right, int bottom) {
final LayerState st = mLayerState;
int N = st.mChildren != null ? st.mChildren.length : 0;
int i = st.mNum;
if (i >= N) {
ChildDrawable[] nu = new ChildDrawable[N + 10];
if (i > 0) {
System.arraycopy(st.mChildren, 0, nu, 0, i);
}
st.mChildren = nu;
}
mLayerState.mChildrenChangingConfigurations |= layer.getChangingConfigurations();
ChildDrawable childDrawable = new ChildDrawable();
st.mChildren[i] = childDrawable;
childDrawable.mId = id;
childDrawable.mDrawable = layer;
childDrawable.mInsetL = left;
childDrawable.mInsetT = top;
childDrawable.mInsetR = right;
childDrawable.mInsetB = bottom;
st.mNum++;
layer.setCallback(this);
}
/**
* Look for a layer with the given id, and returns its {@link Drawable}.
*
* @param id The layer ID to search for.
* @return The {@link Drawable} of the layer that has the given id in the hierarchy or null.
*/
public Drawable findDrawableByLayerId(int id) {
final ChildDrawable[] layers = mLayerState.mChildren;
for (int i = mLayerState.mNum - 1; i >= 0; i--) {
if (layers[i].mId == id) {
return layers[i].mDrawable;
}
}
return null;
}
/**
* Sets the ID of a layer.
*
* @param index The index of the layer which will received the ID.
* @param id The ID to assign to the layer.
*/
public void setId(int index, int id) {
mLayerState.mChildren[index].mId = id;
}
/**
* Returns the number of layers contained within this.
* @return The number of layers.
*/
public int getNumberOfLayers() {
return mLayerState.mNum;
}
/**
* Returns the drawable at the specified layer index.
*
* @param index The layer index of the drawable to retrieve.
*
* @return The {@link android.graphics.drawable.Drawable} at the specified layer index.
*/
public Drawable getDrawable(int index) {
return mLayerState.mChildren[index].mDrawable;
}
/**
* Returns the id of the specified layer.
*
* @param index The index of the layer.
*
* @return The id of the layer or {@link android.view.View#NO_ID} if the layer has no id.
*/
public int getId(int index) {
return mLayerState.mChildren[index].mId;
}
/**
* Sets (or replaces) the {@link Drawable} for the layer with the given id.
*
* @param id The layer ID to search for.
* @param drawable The replacement {@link Drawable}.
* @return Whether the {@link Drawable} was replaced (could return false if
* the id was not found).
*/
public boolean setDrawableByLayerId(int id, Drawable drawable) {
final ChildDrawable[] layers = mLayerState.mChildren;
for (int i = mLayerState.mNum - 1; i >= 0; i--) {
if (layers[i].mId == id) {
layers[i].mDrawable = drawable;
return true;
}
}
return false;
}
/** Specify modifiers to the bounds for the drawable[index].
left += l
top += t;
right -= r;
bottom -= b;
*/
public void setLayerInset(int index, int l, int t, int r, int b) {
ChildDrawable childDrawable = mLayerState.mChildren[index];
childDrawable.mInsetL = l;
childDrawable.mInsetT = t;
childDrawable.mInsetR = r;
childDrawable.mInsetB = b;
}
// overrides from Drawable.Callback
public void invalidateDrawable(Drawable who) {
if (mCallback != null) {
mCallback.invalidateDrawable(this);
}
}
public void scheduleDrawable(Drawable who, Runnable what, long when) {
if (mCallback != null) {
mCallback.scheduleDrawable(this, what, when);
}
}
public void unscheduleDrawable(Drawable who, Runnable what) {
if (mCallback != null) {
mCallback.unscheduleDrawable(this, what);
}
}
// overrides from Drawable
@Override
public void draw(Canvas canvas) {
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
for (int i=0; i<N; i++) {
array[i].mDrawable.draw(canvas);
}
}
@Override
public int getChangingConfigurations() {
return super.getChangingConfigurations()
| mLayerState.mChangingConfigurations
| mLayerState.mChildrenChangingConfigurations;
}
@Override
public boolean getPadding(Rect padding) {
// Arbitrarily get the padding from the first image.
// Technically we should maybe do something more intelligent,
// like take the max padding of all the images.
padding.left = 0;
padding.top = 0;
padding.right = 0;
padding.bottom = 0;
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
for (int i=0; i<N; i++) {
reapplyPadding(i, array[i]);
padding.left += mPaddingL[i];
padding.top += mPaddingT[i];
padding.right += mPaddingR[i];
padding.bottom += mPaddingB[i];
}
return true;
}
@Override
public boolean setVisible(boolean visible, boolean restart) {
boolean changed = super.setVisible(visible, restart);
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
for (int i=0; i<N; i++) {
array[i].mDrawable.setVisible(visible, restart);
}
return changed;
}
@Override
public void setDither(boolean dither) {
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
for (int i=0; i<N; i++) {
array[i].mDrawable.setDither(dither);
}
}
@Override
public void setAlpha(int alpha) {
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
for (int i=0; i<N; i++) {
array[i].mDrawable.setAlpha(alpha);
}
}
@Override
public void setColorFilter(ColorFilter cf) {
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
for (int i=0; i<N; i++) {
array[i].mDrawable.setColorFilter(cf);
}
}
@Override
public int getOpacity() {
return mLayerState.getOpacity();
}
@Override
public boolean isStateful() {
return mLayerState.isStateful();
}
@Override
protected boolean onStateChange(int[] state) {
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
boolean paddingChanged = false;
boolean changed = false;
for (int i=0; i<N; i++) {
final ChildDrawable r = array[i];
if (r.mDrawable.setState(state)) {
changed = true;
}
if (reapplyPadding(i, r)) {
paddingChanged = true;
}
}
if (paddingChanged) {
onBoundsChange(getBounds());
}
return changed;
}
@Override
protected boolean onLevelChange(int level) {
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
boolean paddingChanged = false;
boolean changed = false;
for (int i=0; i<N; i++) {
final ChildDrawable r = array[i];
if (r.mDrawable.setLevel(level)) {
changed = true;
}
if (reapplyPadding(i, r)) {
paddingChanged = true;
}
}
if (paddingChanged) {
onBoundsChange(getBounds());
}
return changed;
}
@Override
protected void onBoundsChange(Rect bounds) {
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
int padL=0, padT=0, padR=0, padB=0;
for (int i=0; i<N; i++) {
final ChildDrawable r = array[i];
r.mDrawable.setBounds(bounds.left + r.mInsetL + padL,
bounds.top + r.mInsetT + padT,
bounds.right - r.mInsetR - padR,
bounds.bottom - r.mInsetB - padB);
padL += mPaddingL[i];
padR += mPaddingR[i];
padT += mPaddingT[i];
padB += mPaddingB[i];
}
}
@Override
public int getIntrinsicWidth() {
int width = -1;
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
int padL=0, padR=0;
for (int i=0; i<N; i++) {
final ChildDrawable r = array[i];
int w = r.mDrawable.getIntrinsicWidth()
+ r.mInsetL + r.mInsetR + padL + padR;
if (w > width) {
width = w;
}
padL += mPaddingL[i];
padR += mPaddingR[i];
}
return width;
}
@Override
public int getIntrinsicHeight() {
int height = -1;
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
int padT=0, padB=0;
for (int i=0; i<N; i++) {
final ChildDrawable r = array[i];
int h = r.mDrawable.getIntrinsicHeight() + r.mInsetT + r.mInsetB + + padT + padB;
if (h > height) {
height = h;
}
padT += mPaddingT[i];
padB += mPaddingB[i];
}
return height;
}
private boolean reapplyPadding(int i, ChildDrawable r) {
final Rect rect = mTmpRect;
r.mDrawable.getPadding(rect);
if (rect.left != mPaddingL[i] || rect.top != mPaddingT[i] ||
rect.right != mPaddingR[i] || rect.bottom != mPaddingB[i]) {
mPaddingL[i] = rect.left;
mPaddingT[i] = rect.top;
mPaddingR[i] = rect.right;
mPaddingB[i] = rect.bottom;
return true;
}
return false;
}
private void ensurePadding() {
final int N = mLayerState.mNum;
if (mPaddingL != null && mPaddingL.length >= N) {
return;
}
mPaddingL = new int[N];
mPaddingT = new int[N];
mPaddingR = new int[N];
mPaddingB = new int[N];
}
@Override
public ConstantState getConstantState() {
if (mLayerState.canConstantState()) {
mLayerState.mChangingConfigurations = super.getChangingConfigurations();
return mLayerState;
}
return null;
}
@Override
public Drawable mutate() {
if (!mMutated && super.mutate() == this) {
final ChildDrawable[] array = mLayerState.mChildren;
final int N = mLayerState.mNum;
for (int i = 0; i < N; i++) {
array[i].mDrawable.mutate();
}
mMutated = true;
}
return this;
}
static class ChildDrawable {
public Drawable mDrawable;
public int mInsetL, mInsetT, mInsetR, mInsetB;
public int mId;
}
static class LayerState extends ConstantState {
int mNum;
ChildDrawable[] mChildren;
int mChangingConfigurations;
int mChildrenChangingConfigurations;
private boolean mHaveOpacity = false;
private int mOpacity;
private boolean mHaveStateful = false;
private boolean mStateful;
private boolean mCheckedConstantState;
private boolean mCanConstantState;
LayerState(LayerState orig, LayerDrawable owner, Resources res) {
if (orig != null) {
final ChildDrawable[] origChildDrawable = orig.mChildren;
final int N = orig.mNum;
mNum = N;
mChildren = new ChildDrawable[N];
mChangingConfigurations = orig.mChangingConfigurations;
mChildrenChangingConfigurations = orig.mChildrenChangingConfigurations;
for (int i = 0; i < N; i++) {
final ChildDrawable r = mChildren[i] = new ChildDrawable();
final ChildDrawable or = origChildDrawable[i];
if (res != null) {
r.mDrawable = or.mDrawable.getConstantState().newDrawable(res);
} else {
r.mDrawable = or.mDrawable.getConstantState().newDrawable();
}
r.mDrawable.setCallback(owner);
r.mInsetL = or.mInsetL;
r.mInsetT = or.mInsetT;
r.mInsetR = or.mInsetR;
r.mInsetB = or.mInsetB;
r.mId = or.mId;
}
mHaveOpacity = orig.mHaveOpacity;
mOpacity = orig.mOpacity;
mHaveStateful = orig.mHaveStateful;
mStateful = orig.mStateful;
mCheckedConstantState = mCanConstantState = true;
} else {
mNum = 0;
mChildren = null;
}
}
@Override
public Drawable newDrawable() {
return new LayerDrawable(this, null);
}
@Override
public Drawable newDrawable(Resources res) {
return new LayerDrawable(this, res);
}
@Override
public int getChangingConfigurations() {
return mChangingConfigurations;
}
public final int getOpacity() {
if (mHaveOpacity) {
return mOpacity;
}
final int N = mNum;
int op = N > 0 ? mChildren[0].mDrawable.getOpacity() : PixelFormat.TRANSPARENT;
for (int i = 1; i < N; i++) {
op = Drawable.resolveOpacity(op, mChildren[i].mDrawable.getOpacity());
}
mOpacity = op;
mHaveOpacity = true;
return op;
}
public final boolean isStateful() {
if (mHaveStateful) {
return mStateful;
}
boolean stateful = false;
final int N = mNum;
for (int i = 0; i < N; i++) {
if (mChildren[i].mDrawable.isStateful()) {
stateful = true;
break;
}
}
mStateful = stateful;
mHaveStateful = true;
return stateful;
}
public synchronized boolean canConstantState() {
if (!mCheckedConstantState && mChildren != null) {
mCanConstantState = true;
final int N = mNum;
for (int i=0; i<N; i++) {
if (mChildren[i].mDrawable.getConstantState() == null) {
mCanConstantState = false;
break;
}
}
mCheckedConstantState = true;
}
return mCanConstantState;
}
}
}
我在values / attrs.xml中有这个
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="LayerDrawableItem">
<attr name="LayerDrawableItem_left" format="dimension" />
<attr name="LayerDrawableItem_top" format="dimension" />
<attr name="LayerDrawableItem_right" format="dimension" />
<attr name="LayerDrawableItem_bottom" format="dimension" />
<attr name="LayerDrawableItem_drawable" format="dimension" />
<attr name="LayerDrawableItem_id" format="dimension" />
</declare-styleable>
</resources>
答案 0 :(得分：0)
您需要添加mCallback成员。由于您是回调，因此mCallback可能是this？