显示存储在使用一个GridView SD卡的图片 [英] Displaying pictures stored on the SD Card using a Gridview
本文介绍了显示存储在使用一个GridView SD卡的图片的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我是比较新的Android和我真的需要这一个帮助。我试图写一些code，将显示使用一个GridView SD卡上的图片，但到目前为止，当我运行在顶部的应用程序只TextView的显示。我想知道，如果在我的code的逻辑严重缺陷的主要活动code，图像适配器类code或两者兼而有之。这是我的code：
I am relatively new to android and I really need help with this one. I am trying to write some code that will display the pictures on the sd card using a GridView, but so far when I run the application only the textview at the top is shown. I would like to know if there is a serious flaw in the logic of my code in the Main Activity code, Image Adapter class code or both. This is my code:
package com.newtestforsdcarddisplay;
import android.app.Activity;
import android.os.Bundle;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.View;
import android.widget.GridView;
import android.widget.AdapterView;
import android.widget.Toast;
import android.provider.MediaStore;
import android.provider.MediaStore.Images.Thumbnails;
import android.net.Uri;
import android.widget.AdapterView.OnItemClickListener;
public class MainActivity extends Activity {
public Cursor myImageCursor;
public int columnNumber;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
String[] imageIDs = new String[]{Thumbnails._ID};
Uri myImagesSource = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
myImageCursor = managedQuery(myImagesSource,
imageIDs, null, null, MediaStore.Images.Thumbnails._ID);
columnNumber = myImageCursor.getColumnIndexOrThrow(MediaStore.Images.Media._ID);
GridView PhoneImageView = (GridView)findViewById(R.id.sdcard);
PhoneImageView.setAdapter(new ImageAdapter(this));
PhoneImageView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
String[] data = { MediaStore.Images.Media.DATA };
Cursor viewImageCursor = managedQuery(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, data,
null, null, MediaStore.Images.Thumbnails._ID );
int imageColumnIndex = viewImageCursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
viewImageCursor.moveToPosition(position);
viewImageCursor.moveToFirst();
String filepath = viewImageCursor.getString(imageColumnIndex);
Toast.makeText(MainActivity.this, filepath, Toast.LENGTH_LONG).show();
Bitmap yourSelectedImage = BitmapFactory.decodeFile(filepath);
}
});
}
}
package com.newtestforsdcarddisplay;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.net.Uri;
import android.provider.MediaStore;
public class ImageAdapter extends BaseAdapter{
final MainActivity pca = new MainActivity();
private Context context;
public ImageAdapter(Context localContext) {
// context = localContext;
}
public int getCount() {
// return pca.myImageCursor.getCount();
return 0;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView picturesView;
if (convertView == null) {
picturesView = new ImageView(context);
// Move cursor to current position
pca.myImageCursor.moveToPosition(position);
// Get the current value for the requested column
int imageID = pca.myImageCursor.getInt(pca.columnNumber);
// Set the content of the image based on the provided URI
picturesView.setImageURI(Uri.withAppendedPath(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, "" + imageID));
picturesView.setScaleType(ImageView.ScaleType.FIT_CENTER);
picturesView.setPadding(8, 8, 8, 8);
picturesView.setLayoutParams(new GridView.LayoutParams(100, 100));
}
else {
picturesView = (ImageView)convertView;
}
return picturesView;
}
}
package com.newtestforsdcarddisplay;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.net.Uri;
import android.provider.MediaStore;
public class ImageAdapter extends BaseAdapter{
final MainActivity pca = new MainActivity();
private Context context;
public ImageAdapter(Context localContext) {
// context = localContext;
}
public int getCount() {
// return pca.myImageCursor.getCount();
return 0;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView picturesView;
if (convertView == null) {
picturesView = new ImageView(context);
// Move cursor to current position
pca.myImageCursor.moveToPosition(position);
// Get the current value for the requested column
int imageID = pca.myImageCursor.getInt(pca.columnNumber);
// Set the content of the image based on the provided URI
picturesView.setImageURI(Uri.withAppendedPath(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, "" + imageID));
picturesView.setScaleType(ImageView.ScaleType.FIT_CENTER);
picturesView.setPadding(8, 8, 8, 8);
picturesView.setLayoutParams(new GridView.LayoutParams(100, 100));
}
else {
picturesView = (ImageView)convertView;
}
return picturesView;
}
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<GridView
android:id="@+id/sdcard"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="10dp"
android:verticalSpacing="10dp"
android:horizontalSpacing="10dp"
android:numColumns="auto_fit"
android:columnWidth="90dp"
android:stretchMode="columnWidth"
android:gravity="center"
/>
</LinearLayout>
可能有人帮我吗????正如我以前说过，我是相当新的Android和我一直在这个挣扎了很长一段时间。任何帮助将非常AP preciated。
Could somebody help me please???? As I said before, I am fairly new to android and I have been struggling with this for a really long time. Any help would VERY MUCH appreciated.
推荐答案
您 getCount将（）将返回0，我认为你应该返回 myImageCursor .getCount（）
your getCount() is returning 0. i think you should return myImageCursor.getCount()
您可以更改构造函数
ImageAdapter(Context ctx,Cursor cr)
{
this.context=ctx;
this.cursor=cr;
}
然后用 cr.getCount（）在适配器的 getCount将（）
这篇关于显示存储在使用一个GridView SD卡的图片的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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