Android手機操作系統的應用方式靈活,簡單,深受廣大編程愛好者的喜愛。尤其是它的開源代碼,使得我們能夠方便的得到自己想要的功能需求。今天我們就為大家帶來了有關Android圖片浏覽的相關方法。
首先是Android圖片浏覽中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">
- < ImageSwitcher Android:id="@+id/switcher"
- Android:layout_width="fill_parent"
- Android:layout_height="fill_parent"
- Android:layout_alignParentTop="true"
- Android:layout_alignParentLeft="true"
- />
- < Gallery Android:id="@+id/gallery"
- Android:background="#55000000"
- Android:layout_width="fill_parent"
- Android:layout_height="60dp"
- Android:layout_alignParentBottom="true"
- Android:layout_alignParentLeft="true"
- Android:gravity="center_vertical"
- Android:spacing="16dp"
- />
- < /RelativeLayout>
layout裡面用到了前面所說的兩個控件,ImageSwitcher用啦顯示全圖,Gallery用來顯示縮略圖。著重看看ImageSwitcher,在ImageSwitcher1中需要實現ViewSwitcher.ViewFactory這個接口,這個接口裡有個方法makeView,這樣就產生了用來顯示圖片的view. ImageSwitcher調用過程是這樣的,首先要有一個Factory為它提供一個View,然後ImageSwitcher就可以初始化各種資源了。注意在使用一個ImageSwitcher之前,一定要調用setFactory方法,要不setImageResource這個方法會報空指針異常。
下面是Android圖片浏覽代碼:
- package com.zx.imageswitcher;
- import Android.app.Activity;
- import Android.content.Context;
- import Android.os.Bundle;
- import Android.view.View;
- import Android.view.ViewGroup;
- import Android.view.animation.AnimationUtils;
- import Android.widget.AdapterView;
- import Android.widget.BaseAdapter;
- import Android.widget.Gallery;
- import Android.widget.ImageSwitcher;
- import Android.widget.ImageView;
- import Android.widget.ViewSwitcher;
- import Android.widget.Gallery.LayoutParams;
- public class ImageSwitcherTest extends Activity implements
- AdapterView.OnItemSelectedListener, ViewSwitcher.ViewFactory{
- private ImageSwitcher mSwitcher;
- private Integer[] mThumbIds = {
- R.drawable.sample_thumb_0, R.drawable.sample_thumb_1,
- R.drawable.sample_thumb_2, R.drawable.sample_thumb_3,
- R.drawable.sample_thumb_4, R.drawable.sample_thumb_5,
- R.drawable.sample_thumb_6, R.drawable.sample_thumb_7};
- private Integer[] mImageIds = {
- R.drawable.sample_0, R.drawable.sample_1, R.drawable.sample_2,
- R.drawable.sample_3, R.drawable.sample_4, R.drawable.sample_5,
- R.drawable.sample_6, R.drawable.sample_7};
- /** Called when the activity is first created. */
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- mSwitcher = (ImageSwitcher) findViewById(R.id.switcher);
- mSwitcher.setFactory(this);
- mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
- Android.R.anim.fade_in));
- mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
- Android.R.anim.fade_out));
- Gallery g = (Gallery) findViewById(R.id.gallery);
- g.setAdapter(new ImageAdapter(this));
- g.setOnItemSelectedListener(this);
- }
- /*
- * override for ViewSwitcher.ViewFactory#makeView()
- */
- public View makeView() {
- ImageView i = new ImageView(this);
- i.setBackgroundColor(0xFF000000);
- i.setScaleType(ImageView.ScaleType.FIT_CENTER);
- i.setLayoutParams(new ImageSwitcher.LayoutParams
(LayoutParams.FILL_PARENT,
- LayoutParams.FILL_PARENT));
- return i;
- }
- /*
- * override for
- * AdapterView.OnItemSelectedListener#onItemSelected()
- */
- public void onItemSelected(AdapterView parent,
View v, int position, long id) {
- mSwitcher.setImageResource(mImageIds[position]);
- }
- /*
- * override for AdapterView.OnItemSelectedListener
#onNothingSelected()
- */
- public void onNothingSelected(AdapterView< ?> arg0) {
- // TODO Auto-generated method stub
- }
- public class ImageAdapter extends BaseAdapter {
- public ImageAdapter(Context c) {
- mContext = c;
- }
- public int getCount() {
- return mThumbIds.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);
- i.setImageResource(mThumbIds[position]);
- i.setAdjustViewBounds(true);
- i.setLayoutParams(new Gallery.LayoutParams(
- LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
- i.setBackgroundResource(R.drawable.picture_frame);
- return i;
- }
- private Context mContext;
- }
- }
從Android圖片浏覽的代碼中看到還實現了AdapterView.OnItemSelectedListener,這樣就需要重寫onItemSelected()方法,然後在該方法中:mSwitcher.setImageResource(mImageIds[position]);這樣就實現了圖片在ImageSwitcher中的切換。