Android的画廊的getView()返回不正确的位置 [英] Android Gallery's getView() returning incorrect position
问题描述
感谢您的阅读!
我采用的是Android画廊既作为的LayoutParams MATCH_PARENT显示一个全屏幕图像的时间。
I am using the Android Gallery with both LayoutParams as MATCH_PARENT to show one full screen image at a time.
下面是我的code:
layout.xml
layout.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent">
<Gallery
android:id="@+id/gallery" android:layout_width="fill_parent"
android:layout_height="fill_parent">
</Gallery>
<TextView android:id="@+id/tvShowText" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:layout_alignParentBottom="true" />
</RelativeLayout>
HelloGallery.java
HelloGallery.java
package com.android.sagar;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
public class HelloGallery extends Activity {
TextView tvShowText = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
tvShowText = (TextView)findViewById(R.id.tvShowText);
Gallery g = (Gallery) findViewById(R.id.gallery);
g.setAdapter(new ImageAdapter(this));
g.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView parent, View v, int position, long id) {
Toast.makeText(HelloGallery.this, "" + position, Toast.LENGTH_SHORT).show();
}
});
}
public class ImageAdapter extends BaseAdapter {
int mGalleryItemBackground;
private Context mContext;
private Integer[] mImageIds = {
R.drawable.pic1,
R.drawable.pic2,
R.drawable.pic3
};
public ImageAdapter(Context c) {
mContext = c;
}
public int getCount() {
return mImageIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i = new ImageView(mContext);
tvShowText.setText("ImageCaption for Image No.: "+position);
i.setImageResource(mImageIds[position]);
i.setLayoutParams(new Gallery.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
i.setScaleType(ImageView.ScaleType.FIT_XY);
i.setBackgroundResource(mGalleryItemBackground);
return i;
}
}
}
在图像显示正常,但我打印的标题是关闭的一个或有时会完全不同。 :(
The images show correctly but the caption that I print is off by one or sometimes totally different. :(
我调试,并发现,当我刷一次,getView()被调用多次 - 约2〜3次......他们都是不同的位置,但图像似乎正在一次。 :( 请帮帮忙!
I debugged and found that when I swipe once, the getView() gets called multiple times - around 2 to 3 times...and they are all different positions but the image appears to be moving one at a time. :( Please help!
推荐答案
为了正确的,你需要重写来更新你的标题画廊
的 OnItemSelectedListener
。 Sujit是在他的评论很正确, getView
被称为为了使(或pre-渲染,或后期渲染在某些情况下),在每一个图像的图库
。它不应该被依赖以识别选择了哪个图像。相反,覆盖 OnItemSelectedListener
在 HelloGallery的onCreate()
方法:
In order to update your caption correctly you need to override the Gallery
's OnItemSelectedListener
. Sujit is correct in his comment that getView
is called in order to render (or pre-render, or post-render in some cases) each image in the Gallery
. It shouldn't be depended on to identify which image is selected. Instead, override OnItemSelectedListener
in your HelloGallery onCreate()
method:
g.setOnItemSelectedListener(new OnItemSelectedListener()
{
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id)
{
tvShowText.setText("ImageCaption for Image No.: "+position);
}
@Override
public void onNothingSelected(AdapterView<?> arg0)
{
tvShowText.setText("No image selected");
}
});
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