BaseAdapter相关

一、机制

二、方法

 三、首先建立item.xml布局 

建立数据源的基础实体类

public class ItemBean {    public int itemImageResid;    public String itemTitle;    public String itemContent;    public ItemBean(int itemImageResid, String itemTitle, String itemContent) {        this.itemImageResid = itemImageResid;        this.itemTitle = itemTitle;        this.itemContent = itemContent;    }}

main activity中的代码 

package com.imooc.baseadaptertest;import android.app.Activity;import android.os.Bundle;import android.widget.ListView;import java.util.ArrayList;import java.util.List;public class MainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        ListView listView = (ListView) findViewById(R.id.lv_main);        List<ItemBean> dataList = new ArrayList<>();        // 创建假数据        for (int i = 0; i < 20; i++) {            dataList.add(new ItemBean(                    R.mipmap.ic_launcher,                    "我是标题" + i,                    "我是内容" + i));        }        // 设置适配器        listView.setAdapter(new MyAdapter(this, dataList));    }}

自定义adapter

package com.imooc.baseadaptertest;import android.content.Context;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.TextView;import java.util.List;public class MyAdapter extends BaseAdapter {    private LayoutInflater mLayoutInflater;    // 映射数据    private List<ItemBean> mDataList;    private long mSumTime;    public MyAdapter(Context context, List<ItemBean> list) {        mLayoutInflater = LayoutInflater.from(context);        mDataList = list;    }    // 获取数据量    @Override    public int getCount() {        return mDataList.size();    }    // 获取对应ID项对应的Item    @Override    public Object getItem(int position) {        return mDataList.get(position);    }    // 获取对应项ID    @Override    public long getItemId(int position) {        return position;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        // 逗比式 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>        // 获取纳秒时间 更加精确        long start = System.nanoTime();        // 由于我们只需要将XML转化为View，并不涉及到具体的布局，所以第二个参数通常设置为null        View view = mLayoutInflater.inflate(R.layout.item, null);        // 实例化控件        ImageView itemImage = (ImageView) view.findViewById(R.id.iv_image);        TextView itemTitle = (TextView) view.findViewById(R.id.tv_title);        TextView itemContent = (TextView) view.findViewById(R.id.tv_content);        // 取出bean对象        ItemBean bean = mDataList.get(position);        // 设置控件的数据        itemImage.setImageResource(bean.itemImageResid);        itemTitle.setText(bean.itemTitle);        itemContent.setText(bean.itemContent);        long end = System.nanoTime();        long dValue = end - start;        mSumTime += dValue;        // 输出每次getView消耗的时间和        Log.d("xys", String.valueOf(mSumTime));        return view;        // 逗比式 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>24409529        // 普通式 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>        // 获取纳秒时间 更加精确//        long start = System.nanoTime();//        if (convertView == null) {        // 由于我们只需要将XML转化为View，并不涉及到具体的布局，所以第二个参数通常设置为null//            convertView = mLayoutInflater.inflate(R.layout.item, null);//        }//        ImageView itemImage = (ImageView) convertView.findViewById(R.id.iv_image);//        TextView itemTitle = (TextView) convertView.findViewById(R.id.tv_title);//        TextView itemContent = (TextView) convertView.findViewById(R.id.tv_content);//        // 取出bean对象//        ItemBean bean = mDataList.get(position);        // 设置控件的数据//        itemImage.setImageResource(bean.itemImageResid);//        itemTitle.setText(bean.itemTitle);//        itemContent.setText(bean.itemContent);//        long end = System.nanoTime();//        long dValue = end - start;//        mSumTime += dValue;        // 输出每次getView消耗的时间和//        Log.d("xys", String.valueOf(mSumTime));//        return convertView;        // 普通式 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>19271161        // 文艺式 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>        // 获取纳秒时间 更加精确//        long start = System.nanoTime();//        ViewHolder holder = null;//        if (convertView == null) {//            holder = new ViewHolder();        // 由于我们只需要将XML转化为View，并不涉及到具体的布局，所以第二个参数通常设置为null//            convertView = mLayoutInflater.inflate(R.layout.item, null);//            holder.img = (ImageView) convertView.findViewById(R.id.iv_image);//            holder.title = (TextView) convertView.findViewById(R.id.tv_title);//            holder.content = (TextView) convertView.findViewById(R.id.tv_content);//            convertView.setTag(holder);//        } else {//            holder = (ViewHolder) convertView.getTag();//        }        // 取出bean对象//        ItemBean bean = mDataList.get(position);        // 设置控件的数据//        holder.img.setImageResource(bean.itemImageResid);//        holder.title.setText(bean.itemTitle);//        holder.content.setText(bean.itemContent);//        long end = System.nanoTime();//        long dValue = end - start;//        mSumTime += dValue;        // 输出每次getView消耗的时间和//        Log.d("xys", String.valueOf(mSumTime));//        return convertView;        // 文艺式 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>16325820    }    // ViewHolder用于缓存控件    class ViewHolder{        public ImageView img;        public TextView title;        public TextView content;    }}

实例二

继承数组adapter但只重写了一个方法

package com.example.imocc_recorder;import java.util.List;import com.example.imocc_recorder.MainActivity.Recorder;import android.content.Context;import android.util.DisplayMetrics;import android.view.Display;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.view.WindowManager;import android.widget.ArrayAdapter;import android.widget.TextView;public class RecorderAdapter extends ArrayAdapter<Recorder>{private List<Recorder> mDatas;private Context mContext;private int mMinItemWidth;private int mMaxItemWidth;private LayoutInflater mLayoutInflater;public RecorderAdapter(Context context, List<Recorder> datas) {super(context, -1, datas);this.mDatas = datas;mContext = context;mLayoutInflater = LayoutInflater.from(context);//获取屏幕的尺寸WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);DisplayMetrics outMetrics = new DisplayMetrics();wm.getDefaultDisplay().getMetrics(outMetrics);mMaxItemWidth = (int) (outMetrics.widthPixels*0.7f);mMinItemWidth = (int) (outMetrics.widthPixels*0.15f);}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {ViewHolder viewHolder = new ViewHolder();if(convertView == null){convertView = mLayoutInflater.inflate(R.layout.item_recorder, parent, false);viewHolder.seconds = (TextView) convertView.findViewById(R.id.id_recorder_time);viewHolder.length = convertView.findViewById(R.id.id_recorder_length);convertView.setTag(viewHolder);}else{viewHolder = (ViewHolder) convertView.getTag();}viewHolder.seconds.setText(Math.round(getItem(position).time)+"\"");ViewGroup.LayoutParams layoutParams = viewHolder.length.getLayoutParams();layoutParams.width = (int)(mMinItemWidth+(mMaxItemWidth/60f*getItem(position).time));return convertView;}class ViewHolder{TextView seconds;View length;}}

调用点

package com.example.imocc_recorder;import java.util.ArrayList;import java.util.List;import com.example.imocc_recorder.view.AudioRecorderButton;import com.example.imocc_recorder.view.AudioRecorderButton.AudioFinishRecorderListener;import android.app.Activity;import android.graphics.drawable.AnimationDrawable;import android.media.MediaPlayer;import android.os.Bundle;import android.view.View;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.ArrayAdapter;import android.widget.ListView;public class MainActivity extends Activity{private ArrayAdapter<Recorder> mAdapter;private List<Recorder> mDatas = new ArrayList<Recorder>();private ListView mListView;private AudioRecorderButton mAudioRecorderButton;private View mAnimView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);mListView = (ListView) findViewById(R.id.id_listview);mAudioRecorderButton = (AudioRecorderButton) findViewById(R.id.id_recorder_button);mAudioRecorderButton.setAudioFinishRecorderListener(new AudioFinishRecorderListener() {@Overridepublic void onFinish(float time, String filepath) {Recorder recorder = new Recorder(time, filepath);mDatas.add(recorder);mAdapter.notifyDataSetChanged();mListView.setSelection(mDatas.size()-1);}});mAdapter = new RecorderAdapter(this, mDatas);mListView.setAdapter(mAdapter);mListView.setOnItemClickListener(new OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> parent, View view,int position, long id) {//新建play_anim.xml文件//播放帧动画//当一个播放时，点击下一个时，停止前一个动画播放if(mAnimView!=null){mAnimView.setBackgroundResource(R.drawable.adj);mAnimView=null;}mAnimView = view.findViewById(R.id.id_recorder_anim);mAnimView.setBackgroundResource(R.drawable.play_anim);AnimationDrawable anim = (AnimationDrawable) mAnimView.getBackground();anim.start();//播放音频MediaManager.playSound(mDatas.get(position).filePath, new MediaPlayer.OnCompletionListener(){@Overridepublic void onCompletion(MediaPlayer mp) {mAnimView.setBackgroundResource(R.drawable.adj);}});}});}@Overrideprotected void onPause() {super.onPause();MediaManager.pause();}@Overrideprotected void onResume() {super.onResume();MediaManager.resume();}@Overrideprotected void onDestroy() {super.onDestroy();MediaManager.release();}class Recorder{float time;String filePath;public Recorder(float time, String filePath) {this.time = time;this.filePath = filePath;}public float getTime() {return time;}public void setTime(float time) {this.time = time;}public String getFilePath() {return filePath;}public void setFilePath(String filePath) {this.filePath = filePath;}}}