Android 关于GridView 以及图片处理一些知识
Android 关于GridView 以及图片处理一些知识
Android 关于GridView控件的处理
本人一直以为做一般的Android应用开发,其中创意也就是有好的Idea是至关重要的,其次是要有解决一般问题的想法,如如何实现一个应用兼容多种屏幕分辨率的问题(即使android对于图片的处理,默认情况先是自适应的,即等比例或缩放图片),如何自己实现网络图片的分段下载,如何实现不同Activity之间的数据传递问题,当Listview中数据量过大时,如何实现数据的分批下载等问题。结果上周去参加了一个面试,呜呜---,让当场编写一个GridView实现手机SDcard内置图片的Thumb nail以及图片的修剪也翻转问题。以前都是现用现查文档或者帮助的,以至于当时傻眼了,控件都不知道怎么用,哎,离开了网络感觉什么都干不了啊,今天下午有些闲暇就整理了一个应用,实现其功能。先看下源代码实现了对图片的Thumbnails功能:
- package com.daisy.android.components;
- import java.io.File;
- import java.util.ArrayList;
- import java.util.HashMap;
- import java.util.List;
- import java.util.Map;
- import android.app.Activity;
- import android.content.Context;
- import android.content.Intent;
- import android.graphics.Bitmap;
- import android.graphics.BitmapFactory;
- import android.net.Uri;
- import android.os.Bundle;
- import android.util.Log;
- import android.view.View;
- import android.widget.AdapterView;
- import android.widget.GridView;
- import android.widget.ImageView;
- import android.widget.ListAdapter;
- import android.widget.SimpleAdapter;
- import android.widget.AdapterView.OnItemClickListener;
- public class GridViewActivity extends Activity {
- public static String TAG = "Grid_view";
- private GridView gridView;
- private ArrayList<HashMap<String, String>> list;
- /** Called when the activity is first created. */
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- findView();
- }
- private void findView() {
- gridView = (GridView) findViewById(R.id.gridview);
- list = new ArrayList();
- filepath("/sdcard");
- // test the contents in the list
- for (int i = 0; i < list.size(); i++) {
- Log.i(TAG, list.get(i).get("path") + "-----");
- }
- String[] from = { "path" };
- int[] to = { R.id.imageView };
- ListAdapter adapter = new GridAdapter(this, list, R.layout.item, from,
- to);
- gridView.setAdapter(adapter);
- gridView.setOnItemClickListener(listener);
- }
- OnItemClickListener listener = new OnItemClickListener() {
- @Override
- public void onItemClick(AdapterView<?> parent, View view, int position,
- long id) {
- // TODO Auto-generated method stub
- String imagePath = list.get(position).get("path");
- Intent intent = new Intent(GridViewActivity.this, ImageViewer.class);
- intent.putExtra("path", imagePath);
- startActivity(intent);
- }
- };
- public void filepath(String str) {
- Log.i(TAG, str + "---path---");
- File file = new File(str);
- if (file.isDirectory()) {
- String[] filePath = file.list();
- for (String path : filePath) {
- file = new File(str + "/" + path);
- if (file.isDirectory() && !path.equals("DCIM")) {
- filepath(str + "/" + path);
- } else if (path.endsWith(".jpg")) {
- HashMap hash = new HashMap();
- hash.put("path", str + "/" + path);
- list.add(hash);
- }
- }
- }
- }
- class GridAdapter extends SimpleAdapter {
- public GridAdapter(Context context,
- List<? extends Map<String, ?>> data, int resource,
- String[] from, int[] to) {
- super(context, data, resource, from, to);
- // TODO Auto-generated constructor stub
- }
- // set the imageView using the path of image
- public void setViewImage(ImageView v, String value) {
- try {
- Bitmap bitmap = BitmapFactory.decodeFile(value);
- Bitmap newBit = Bitmap
- .createScaledBitmap(bitmap, 100, 80, true);
- v.setImageBitmap(newBit);
- } catch (NumberFormatException nfe) {
- v.setImageURI(Uri.parse(value));
- }
- }
- }
- }
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