Java android如何在加载新图像之前回收图像
我有一个内存不足的问题,在这里我有全屏图像显示。我想全屏显示图像,我有两个按钮,可以向左或向右循环。如何在显示下一个图像之前回收以前的图像以防止内存不足异常?还是有更好的方法 这是我的课堂,我在其中查看图像Java android如何在加载新图像之前回收图像,java,android,Java,Android,我有一个内存不足的问题,在这里我有全屏图像显示。我想全屏显示图像,我有两个按钮,可以向左或向右循环。如何在显示下一个图像之前回收以前的图像以防止内存不足异常?还是有更好的方法 这是我的课堂,我在其中查看图像 public class ImageViewActivity extends Activity { private Button btnHome; private Button btnBack; private ImageButton btnLeft; private ImageButton
public class ImageViewActivity extends Activity
{
private Button btnHome;
private Button btnBack;
private ImageButton btnLeft;
private ImageButton btnRight;
ImageView imageView;
RelativeLayout layout;
int height;
int width;
Bitmap bitmap;
String[] imagesPath;
int position;
// These matrices will be used to move and zoom image
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;
String savedItemClicked;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.imageview_activity);
btnHome = (Button) findViewById(R.id.btnHome);
btnBack = (Button) findViewById(R.id.btnBack);
btnLeft = (ImageButton) findViewById(R.id.leftArrow);
btnRight = (ImageButton) findViewById(R.id.rightArrow);
DisplayMetrics displayMetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
height = displayMetrics.heightPixels;
width = displayMetrics.widthPixels;
imagesPath = getIntent().getStringExtra("IMAGES").split("\\|");
position = getIntent().getIntExtra("POSITION", 0);
bitmap = BitmapFactory.decodeFile(imagesPath[position]);
imageView = (ImageView)findViewById(R.id.displayImage);
imageView.setImageBitmap(Bitmap.createScaledBitmap(bitmap, width, height, false));
btnLeft.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0)
{
if (position == 0)
position = 5;
else
position--;
RectF imageRectF = new RectF(0, 0, width, height);
RectF viewRectF = new RectF(0, 0, width, height);
matrix.setRectToRect(imageRectF, viewRectF, Matrix.ScaleToFit.CENTER);
bitmap = BitmapFactory.decodeFile(imagesPath[position]);
ImageView imageView = (ImageView)findViewById(R.id.displayImage);
imageView.setImageBitmap(Bitmap.createScaledBitmap(bitmap, width, height, false));
imageView.setImageMatrix(matrix);
}
});
btnRight.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0)
{
if (position == 5)
position = 0;
else
position++;
RectF imageRectF = new RectF(0, 0, width, height);
RectF viewRectF = new RectF(0, 0, width, height);
matrix.setRectToRect(imageRectF, viewRectF, Matrix.ScaleToFit.CENTER);
bitmap = BitmapFactory.decodeFile(imagesPath[position]);
ImageView imageView = (ImageView)findViewById(R.id.displayImage);
imageView.setImageBitmap(Bitmap.createScaledBitmap(bitmap, width, height, false));
imageView.setImageMatrix(matrix);
}
});
btnHome.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0)
{
Intent ActivitySwitch = new Intent(getApplicationContext(), MainMenuActivity.class);
startActivity(ActivitySwitch);
}
});
btnBack.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0)
{
Intent ActivitySwitch = new Intent(getApplicationContext(), AddClientActivity.class);
startActivity(ActivitySwitch);
}
});
imageView.setOnTouchListener(new View.OnTouchListener()
{
@Override
public boolean onTouch(View v, MotionEvent event)
{
ImageView view = (ImageView) v;
dumpEvent(event);
// Handle touch events here...
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:
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 void dumpEvent(MotionEvent event) {
String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",
"POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };
StringBuilder sb = new StringBuilder();
int action = event.getAction();
int actionCode = action & MotionEvent.ACTION_MASK;
sb.append("event ACTION_").append(names[actionCode]);
if (actionCode == MotionEvent.ACTION_POINTER_DOWN
|| actionCode == MotionEvent.ACTION_POINTER_UP) {
sb.append("(pid ").append(
action >> MotionEvent.ACTION_POINTER_ID_SHIFT);
sb.append(")");
}
sb.append("[");
for (int i = 0; i < event.getPointerCount(); i++) {
sb.append("#").append(i);
sb.append("(pid ").append(event.getPointerId(i));
sb.append(")=").append((int) event.getX(i));
sb.append(",").append((int) event.getY(i));
if (i + 1 < event.getPointerCount())
sb.append(";");
}
sb.append("]");
}
/** Determine the space between the first two fingers */
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (float)Math.sqrt(x * x + y * y);
}
/** Calculate the mid point of the first two fingers */
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);
}
公共类ImageViewActivity扩展活动
{
私人按钮btnHome;
私人按钮btnBack;
私人图像按钮btnLeft;
私人图像按钮btnRight;
图像视图图像视图;
相对布局;
内部高度;
整数宽度;
位图;
字符串[]imagesPath;
内部位置;
//这些矩阵将用于移动和缩放图像
矩阵=新矩阵();
矩阵savedMatrix=新矩阵();
//我们可能处于这三种状态之一
静态最终int NONE=0;
静态最终整数阻力=1;
静态最终整数缩放=2;
int模式=无;
//记住一些关于缩放的事情
PointF start=新的PointF();
PointF mid=新的PointF();
浮动oldDist=1f;
字符串savedItemClicked;
@凌驾
创建时的公共void(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.imageview_活动);
btnHome=(按钮)findViewById(R.id.btnHome);
btnBack=(按钮)findViewById(R.id.btnBack);
btnLeft=(ImageButton)findViewById(R.id.leftArrow);
btnRight=(ImageButton)findViewById(R.id.rightArrow);
DisplayMetrics DisplayMetrics=新的DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
高度=displayMetrics.heightPixels;
宽度=displayMetrics.widthPixels;
imagesPath=getIntent().getStringExtra(“图像”).split(“\\\\\”);
位置=getIntent().getIntExtra(“位置”,0);
位图=BitmapFactory.decodeFile(imagesPath[position]);
imageView=(imageView)findViewById(R.id.displayImage);
setImageBitmap(位图.createScaledBitmap(位图、宽度、高度、假));
btnLeft.setOnClickListener(新视图.OnClickListener()
{
公共void onClick(视图arg0)
{
如果(位置==0)
位置=5;
其他的
位置--;
RectF imageRectF=新的RectF(0,0,宽度,高度);
RectF viewRectF=新的RectF(0,0,宽度,高度);
matrix.SetRectRect(imageRectF、viewRectF、matrix.ScaleToFit.CENTER);
位图=BitmapFactory.decodeFile(imagesPath[position]);
ImageView ImageView=(ImageView)findViewById(R.id.displayImage);
setImageBitmap(位图.createScaledBitmap(位图、宽度、高度、假));
设置图像矩阵(矩阵);
}
});
btnRight.setOnClickListener(新视图.OnClickListener()
{
公共void onClick(视图arg0)
{
如果(位置==5)
位置=0;
其他的
位置++;
RectF imageRectF=新的RectF(0,0,宽度,高度);
RectF viewRectF=新的RectF(0,0,宽度,高度);
matrix.SetRectRect(imageRectF、viewRectF、matrix.ScaleToFit.CENTER);
位图=BitmapFactory.decodeFile(imagesPath[position]);
ImageView ImageView=(ImageView)findViewById(R.id.displayImage);
setImageBitmap(位图.createScaledBitmap(位图、宽度、高度、假));
设置图像矩阵(矩阵);
}
});
btnHome.setOnClickListener(新视图.OnClickListener()
{
公共void onClick(视图arg0)
{
Intent-ActivitySwitch=new-Intent(getApplicationContext(),MainMenuActivity.class);
启动触觉(活动开关);
}
});
btnBack.setOnClickListener(新视图.OnClickListener()
{
公共void onClick(视图arg0)
{
Intent-ActivitySwitch=new-Intent(getApplicationContext(),AddClientActivity.class);
启动触觉(活动开关);
}
});
imageView.setOnTouchListener(新视图.OnTouchListener()
{
@凌驾
公共布尔onTouch(视图v,运动事件)
{
ImageView视图=(ImageView)v;
dumpEvent(事件);
//在这里处理触摸事件。。。
开关(event.getAction()&MotionEvent.ACTION\u掩码){
case MotionEvent.ACTION\u DOWN:
savedMatrix.set(矩阵);
set(event.getX(),event.getY());
模式=拖动;
打破
case MotionEvent.ACTION\u指针\u向下:
oldDist=间距(事件);
如果(旧区>10f){
savedMatrix.set(矩阵);
中点(中点,事件);
模式=缩放;
}
打破
case MotionEvent.ACTION\u UP:
case MotionEvent.ACTION\u指针\u向上:
模式=无;
打破
case MotionEvent.ACTION\u移动:
如果(模式==拖动){
// ...
矩阵集(savedMatrix);
postTranslate(event.getX()-start.x,event.getY())
-开始(y);
}else if(模式==缩放){
float newDist=间距(事件);
如果(新距离>10f){
矩阵集(savedMatrix);
浮动比例=新距离/旧距离;
矩阵。后标度(标度、标度、中x、中y);
}
}
打破
}
视图.setImageMatrix(矩阵);
返回true;
}
});
}
私有void转储事件(MotionEvent事件){
字符串名称[]={“向下”、“向上”、“移动”、“取消”、“外部”,
Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView);
bitmap.recycle();