我有一个用户可以在我的Android应用程序中绘制的图像。我决定添加一个撤消按钮，以便用户可以取消错误。我这样做是为了当用户在屏幕上绘图时，它将位图保存到数组中。然后，当按下撤消按钮时，它会将图像更改为阵列中的最后一个位图。但是，这只是将图像设置为当前图像（即它根本不会改变它）。
public class edit extends AppCompatActivity implements View.OnClickListener {
float MoveX,MoveY,DownY,DownX,UpY=0,UpX ;
List<Bitmap> undos = new ArrayList<Bitmap>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_edit);
final ImageButton btn2 = (ImageButton) findViewById(R.id.imageButton2);
btn2.setOnClickListener(this);
final Button buttonchoose = (Button) findViewById(R.id.buttonchoose);
buttonchoose.setOnClickListener(this);
final RelativeLayout ViewX = (RelativeLayout) findViewById(R.id.RLXV);
ViewTreeObserver vto = ViewX.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
ViewX.getViewTreeObserver().removeOnGlobalLayoutListener(this);
Intent intent7 = getIntent();
String bitmapXY = (String) intent7.getExtras().get("BitmapImage");
GraphRequest request = GraphRequest.newGraphPathRequest(
AccessToken.getCurrentAccessToken(),
"/" + bitmapXY,
new GraphRequest.Callback() {
@Override
public void onCompleted(GraphResponse response) {
HttpURLConnection connection = null;
try {
int ViewWidth = ViewX.getMeasuredWidth();
JSONObject photos = response.getJSONObject();
JSONArray linkY = photos.optJSONArray("images");
final JSONObject linkO = linkY.optJSONObject(0);
final String link2 = linkO.optString("source");
URL LINKF = new URL(link2);
connection = (HttpURLConnection) LINKF.openConnection();
connection.setDoInput(true);
connection.connect();
InputStream input = connection.getInputStream();
Bitmap bitmap = BitmapFactory.decodeStream(input);
float HH = (float) bitmap.getHeight();
float WW = (float) bitmap.getWidth();
float ViewWidthX = (float) ViewWidth;
float height = (HH / WW) * ViewWidthX;
Bitmap bitmapF = Bitmap.createScaledBitmap(bitmap, ViewWidth, Math.round(height), false);
final ImageView image1 = (ImageView) findViewById(R.id.image1);
image1.setImageBitmap(bitmapF);
undos.add(bitmapF);
image1.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
Display d = getWindowManager().getDefaultDisplay();
float dw = d.getWidth();
float dh = d.getHeight();
float x = event.getX();
float y = event.getY();
float r = 2;
Bitmap BTX = ((BitmapDrawable)image1.getDrawable()).getBitmap();
Canvas canvas = new Canvas(BTX);
canvas.drawBitmap(BTX,0,0,null);
Paint paint1 = new Paint();
int bg1 = buttonchoose.getDrawingCacheBackgroundColor();
ColorDrawable buttonColor = (ColorDrawable) buttonchoose.getBackground();
int bg2 =buttonColor.getColor();
paint1.setColor(bg2);
paint1.setShadowLayer(5, 2, 2, bg2);
paint1.setStrokeWidth(20);
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
DownY = event.getY();
DownX = event.getX();
break;
case MotionEvent.ACTION_MOVE:
MoveY = event.getY();
MoveX = event.getX();
canvas.drawLine(DownX, DownY, MoveX, MoveY, paint1);
image1.invalidate();
DownX = MoveX;
DownY=MoveY;
break;
case MotionEvent.ACTION_UP:
UpY = event.getY();
UpX = event.getX();
canvas.drawLine(DownX, DownY, UpX, UpY, paint1);
image1.invalidate();
Bitmap BTXYZ = ((BitmapDrawable)image1.getDrawable()).getBitmap();
break;
}
return true;
}
});
} catch (IOException e) {
e.printStackTrace();
}
}
});
Bundle parameters = new Bundle();
parameters.putString("fields", "images");
request.setParameters(parameters);
request.executeAsync();
}
});
}
@Override
public void onClick(View v) {
switch(v.getId()) {
case R.id.buttonchoose:
final ColorPicker cp = new ColorPicker(edit.this, 0, 0, 0);
/* Show color picker dialog */
cp.show();
/* On Click listener for the dialog, when the user select the color */
Button okColor = (Button) cp.findViewById(R.id.okColorButton);
okColor.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
/* You can get single channel (value 0-255) */
int selectedColorR = cp.getRed();
int selectedColorG = cp.getGreen();
int selectedColorB = cp.getBlue();
/* Or the android RGB Color (see the android Color class reference) */
int selectedColorRGB = cp.getColor();
Button buttonchoose = (Button) findViewById(R.id.buttonchoose);
buttonchoose.setText("");
buttonchoose.setBackgroundColor(selectedColorRGB);
cp.dismiss();
}
});
break;
case R.id.imageButton2:
int newImage = undos.size();
Log.e("Lenght of Array",""+newImage);
if(newImage >=1) {
Bitmap newImage2 = undos.get(newImage-2);
ImageView IMGXV = (ImageView) findViewById(R.id.image1);
IMGXV.setImageBitmap(newImage2);
undos.remove(newImage-1);
}
break;
}
}
}
答案 0 :(得分：0)
试试这个确切的代码 -
Bitmap bitmapF = Bitmap.createScaledBitmap(bitmap, ViewWidth, Math.round(height), false);
final ImageView image1 = (ImageView) findViewById(R.id.image1);
image1.setImageBitmap(bitmapF);
//The extra line before adding bitmap to arraylist.
Bitmap bitmapFcopy = bitmapFcopy.copy(bitmapFcopy.getConfig(), true);
undos.add(bitmapFcopy);
编辑在onGlobalLayout（）中添加了额外的一行，试试这个 -
public class edit extends AppCompatActivity implements View.OnClickListener {
//Declare the imageview here and access this everywhere.
ImageView image1;
float MoveX,MoveY,DownY,DownX,UpY=0,UpX ;
List<Bitmap> undos = new ArrayList<Bitmap>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_edit);
//Get the reference here
image1 = (ImageView) findViewById(R.id.image1);
final ImageButton btn2 = (ImageButton) findViewById(R.id.imageButton2);
btn2.setOnClickListener(this);
final Button buttonchoose = (Button) findViewById(R.id.buttonchoose);
buttonchoose.setOnClickListener(this);
final RelativeLayout ViewX = (RelativeLayout) findViewById(R.id.RLXV);
ViewTreeObserver vto = ViewX.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
ViewX.getViewTreeObserver().removeOnGlobalLayoutListener(this);
Intent intent7 = getIntent();
String bitmapXY = (String) intent7.getExtras().get("BitmapImage");
GraphRequest request = GraphRequest.newGraphPathRequest(
AccessToken.getCurrentAccessToken(),
"/" + bitmapXY,
new GraphRequest.Callback() {
@Override
public void onCompleted(GraphResponse response) {
HttpURLConnection connection = null;
try {
int ViewWidth = ViewX.getMeasuredWidth();
JSONObject photos = response.getJSONObject();
JSONArray linkY = photos.optJSONArray("images");
final JSONObject linkO = linkY.optJSONObject(0);
final String link2 = linkO.optString("source");
URL LINKF = new URL(link2);
connection = (HttpURLConnection) LINKF.openConnection();
connection.setDoInput(true);
connection.connect();
InputStream input = connection.getInputStream();
Bitmap bitmap = BitmapFactory.decodeStream(input);
float HH = (float) bitmap.getHeight();
float WW = (float) bitmap.getWidth();
float ViewWidthX = (float) ViewWidth;
float height = (HH / WW) * ViewWidthX;
Bitmap bitmapF = Bitmap.createScaledBitmap(bitmap, ViewWidth, Math.round(height), false);
//Remove from here and declare this in onCreate() and don't make it final
//final ImageView image1 = (ImageView) findViewById(R.id.image1);
image1.setImageBitmap(bitmapF);
undos.add(bitmapF);
image1.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
Display d = getWindowManager().getDefaultDisplay();
float dw = d.getWidth();
float dh = d.getHeight();
float x = event.getX();
float y = event.getY();
float r = 2;
Bitmap BTX = ((BitmapDrawable)image1.getDrawable()).getBitmap();
Canvas canvas = new Canvas(BTX);
canvas.drawBitmap(BTX,0,0,null);
Paint paint1 = new Paint();
int bg1 = buttonchoose.getDrawingCacheBackgroundColor();
ColorDrawable buttonColor = (ColorDrawable) buttonchoose.getBackground();
int bg2 =buttonColor.getColor();
paint1.setColor(bg2);
paint1.setShadowLayer(5, 2, 2, bg2);
paint1.setStrokeWidth(20);
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
DownY = event.getY();
DownX = event.getX();
break;
case MotionEvent.ACTION_MOVE:
MoveY = event.getY();
MoveX = event.getX();
canvas.drawLine(DownX, DownY, MoveX, MoveY, paint1);
image1.invalidate();
DownX = MoveX;
DownY=MoveY;
break;
case MotionEvent.ACTION_UP:
UpY = event.getY();
UpX = event.getX();
canvas.drawLine(DownX, DownY, UpX, UpY, paint1);
image1.invalidate();
Bitmap BTXYZ = ((BitmapDrawable)image1.getDrawable()).getBitmap();
break;
}
return true;
}
});
} catch (IOException e) {
e.printStackTrace();
}
}
});
Bundle parameters = new Bundle();
parameters.putString("fields", "images");
request.setParameters(parameters);
request.executeAsync();
}
});
}
@Override
public void onClick(View v) {
switch(v.getId()) {
case R.id.buttonchoose:
final ColorPicker cp = new ColorPicker(edit.this, 0, 0, 0);
/* Show color picker dialog */
cp.show();
/* On Click listener for the dialog, when the user select the color */
Button okColor = (Button) cp.findViewById(R.id.okColorButton);
okColor.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
/* You can get single channel (value 0-255) */
int selectedColorR = cp.getRed();
int selectedColorG = cp.getGreen();
int selectedColorB = cp.getBlue();
/* Or the android RGB Color (see the android Color class reference) */
int selectedColorRGB = cp.getColor();
Button buttonchoose = (Button) findViewById(R.id.buttonchoose);
buttonchoose.setText("");
buttonchoose.setBackgroundColor(selectedColorRGB);
cp.dismiss();
}
});
break;
case R.id.imageButton2:
int newImage = undos.size();
Log.e("Lenght of Array",""+newImage);
if(newImage >=1) {
Bitmap newImage2 = undos.get(newImage-2);
//Don't take reference again here
//ImageView IMGXV = (ImageView) findViewById(R.id.image1);
image1.setImageBitmap(newImage2);
undos.remove(newImage-1);
}
break;
}
}
}
编辑2
def auto_init(local_name_space):
"""Set instance attributes from arguments.
"""
self = local_name_space.pop('self')
for name, value in local_name_space.items():
setattr(self, name, value)