Android中ListView下拉重新整理的實現
阿新 • • 發佈：2018-12-30
ListView中的下拉重新整理是非常常見的，也是經常使用的，看到有很多同學想要，那我就整理一下，供大家參考。那我就不解釋，直接上程式碼了。
這裡需要自己重寫一下ListView,重寫程式碼如下:
package net.loonggg.listview; import java.util.Date; import android.content.Context; import android.util.AttributeSet; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.view.animation.LinearInterpolator; import android.view.animation.RotateAnimation; import android.widget.AbsListView; import android.widget.AbsListView.OnScrollListener; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.ListView; import android.widget.ProgressBar; import android.widget.TextView; public class MyListView extends ListView implements OnScrollListener { private final static int RELEASE_To_REFRESH = 0;// 下拉過程的狀態值 private final static int PULL_To_REFRESH = 1; // 從下拉返回到不重新整理的狀態值 private final static int REFRESHING = 2;// 正在重新整理的狀態值 private final static int DONE = 3; private final static int LOADING = 4; // 實際的padding的距離與介面上偏移距離的比例 private final static int RATIO = 3; private LayoutInflater inflater; // ListView頭部下拉重新整理的佈局 private LinearLayout headerView; private TextView lvHeaderTipsTv; private TextView lvHeaderLastUpdatedTv; private ImageView lvHeaderArrowIv; private ProgressBar lvHeaderProgressBar; // 定義頭部下拉重新整理的佈局的高度 private int headerContentHeight; private RotateAnimation animation; private RotateAnimation reverseAnimation; private int startY; private int state; private boolean isBack; // 用於保證startY的值在一個完整的touch事件中只被記錄一次 private boolean isRecored; private OnRefreshListener refreshListener; private boolean isRefreshable; public MyListView(Context context) { super(context); init(context); } public MyListView(Context context, AttributeSet attrs) { super(context, attrs); init(context); } private void init(Context context) { setCacheColorHint(context.getResources().getColor(R.color.transparent)); inflater = LayoutInflater.from(context); headerView = (LinearLayout) inflater.inflate(R.layout.lv_header, null); lvHeaderTipsTv = (TextView) headerView .findViewById(R.id.lvHeaderTipsTv); lvHeaderLastUpdatedTv = (TextView) headerView .findViewById(R.id.lvHeaderLastUpdatedTv); lvHeaderArrowIv = (ImageView) headerView .findViewById(R.id.lvHeaderArrowIv); // 設定下拉重新整理圖示的最小高度和寬度 lvHeaderArrowIv.setMinimumWidth(70); lvHeaderArrowIv.setMinimumHeight(50); lvHeaderProgressBar = (ProgressBar) headerView .findViewById(R.id.lvHeaderProgressBar); measureView(headerView); headerContentHeight = headerView.getMeasuredHeight(); // 設定內邊距，正好距離頂部為一個負的整個佈局的高度，正好把頭部隱藏 headerView.setPadding(0, -1 * headerContentHeight, 0, 0); // 重繪一下 headerView.invalidate(); // 將下拉重新整理的佈局加入ListView的頂部 addHeaderView(headerView, null, false); // 設定滾動監聽事件 setOnScrollListener(this); // 設定旋轉動畫事件 animation = new RotateAnimation(0, -180, RotateAnimation.RELATIVE_TO_SELF, 0.5f, RotateAnimation.RELATIVE_TO_SELF, 0.5f); animation.setInterpolator(new LinearInterpolator()); animation.setDuration(250); animation.setFillAfter(true); reverseAnimation = new RotateAnimation(-180, 0, RotateAnimation.RELATIVE_TO_SELF, 0.5f, RotateAnimation.RELATIVE_TO_SELF, 0.5f); reverseAnimation.setInterpolator(new LinearInterpolator()); reverseAnimation.setDuration(200); reverseAnimation.setFillAfter(true); // 一開始的狀態就是下拉重新整理完的狀態，所以為DONE state = DONE; // 是否正在重新整理 isRefreshable = false; } @Override public void onScrollStateChanged(AbsListView view, int scrollState) { } @Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { if (firstVisibleItem == 0) { isRefreshable = true; } else { isRefreshable = false; } } @Override public boolean onTouchEvent(MotionEvent ev) { if (isRefreshable) { switch (ev.getAction()) { case MotionEvent.ACTION_DOWN: if (!isRecored) { isRecored = true; startY = (int) ev.getY();// 手指按下時記錄當前位置 } break; case MotionEvent.ACTION_UP: if (state != REFRESHING && state != LOADING) { if (state == PULL_To_REFRESH) { state = DONE; changeHeaderViewByState(); } if (state == RELEASE_To_REFRESH) { state = REFRESHING; changeHeaderViewByState(); onLvRefresh(); } } isRecored = false; isBack = false; break; case MotionEvent.ACTION_MOVE: int tempY = (int) ev.getY(); if (!isRecored) { isRecored = true; startY = tempY; } if (state != REFRESHING && isRecored && state != LOADING) { // 保證在設定padding的過程中，當前的位置一直是在head，否則如果當列表超出螢幕的話，當在上推的時候，列表會同時進行滾動 // 可以鬆手去重新整理了 if (state == RELEASE_To_REFRESH) { setSelection(0); // 往上推了，推到了螢幕足夠掩蓋head的程度，但是還沒有推到全部掩蓋的地步 if (((tempY - startY) / RATIO < headerContentHeight)// 由鬆開重新整理狀態轉變到下拉重新整理狀態 && (tempY - startY) > 0) { state = PULL_To_REFRESH; changeHeaderViewByState(); } // 一下子推到頂了 else if (tempY - startY <= 0) {// 由鬆開重新整理狀態轉變到done狀態 state = DONE; changeHeaderViewByState(); } } // 還沒有到達顯示鬆開重新整理的時候,DONE或者是PULL_To_REFRESH狀態 if (state == PULL_To_REFRESH) { setSelection(0); // 下拉到可以進入RELEASE_TO_REFRESH的狀態 if ((tempY - startY) / RATIO >= headerContentHeight) {// 由done或者下拉重新整理狀態轉變到鬆開重新整理 state = RELEASE_To_REFRESH; isBack = true; changeHeaderViewByState(); } // 上推到頂了 else if (tempY - startY <= 0) {// 由DOne或者下拉重新整理狀態轉變到done狀態 state = DONE; changeHeaderViewByState(); } } // done狀態下 if (state == DONE) { if (tempY - startY > 0) { state = PULL_To_REFRESH; changeHeaderViewByState(); } } // 更新headView的size if (state == PULL_To_REFRESH) { headerView.setPadding(0, -1 * headerContentHeight + (tempY - startY) / RATIO, 0, 0); } // 更新headView的paddingTop if (state == RELEASE_To_REFRESH) { headerView.setPadding(0, (tempY - startY) / RATIO - headerContentHeight, 0, 0); } } break; default: break; } } return super.onTouchEvent(ev); } // 當狀態改變時候，呼叫該方法，以更新介面 private void changeHeaderViewByState() { switch (state) { case RELEASE_To_REFRESH: lvHeaderArrowIv.setVisibility(View.VISIBLE); lvHeaderProgressBar.setVisibility(View.GONE); lvHeaderTipsTv.setVisibility(View.VISIBLE); lvHeaderLastUpdatedTv.setVisibility(View.VISIBLE); lvHeaderArrowIv.clearAnimation();// 清除動畫 lvHeaderArrowIv.startAnimation(animation);// 開始動畫效果 lvHeaderTipsTv.setText("鬆開重新整理"); break; case PULL_To_REFRESH: lvHeaderProgressBar.setVisibility(View.GONE); lvHeaderTipsTv.setVisibility(View.VISIBLE); lvHeaderLastUpdatedTv.setVisibility(View.VISIBLE); lvHeaderArrowIv.clearAnimation(); lvHeaderArrowIv.setVisibility(View.VISIBLE); // 是由RELEASE_To_REFRESH狀態轉變來的 if (isBack) { isBack = false; lvHeaderArrowIv.clearAnimation(); lvHeaderArrowIv.startAnimation(reverseAnimation); lvHeaderTipsTv.setText("下拉重新整理"); } else { lvHeaderTipsTv.setText("下拉重新整理"); } break; case REFRESHING: headerView.setPadding(0, 0, 0, 0); lvHeaderProgressBar.setVisibility(View.VISIBLE); lvHeaderArrowIv.clearAnimation(); lvHeaderArrowIv.setVisibility(View.GONE); lvHeaderTipsTv.setText("正在重新整理..."); lvHeaderLastUpdatedTv.setVisibility(View.VISIBLE); break; case DONE: headerView.setPadding(0, -1 * headerContentHeight, 0, 0); lvHeaderProgressBar.setVisibility(View.GONE); lvHeaderArrowIv.clearAnimation(); lvHeaderArrowIv.setImageResource(R.drawable.arrow); lvHeaderTipsTv.setText("下拉重新整理"); lvHeaderLastUpdatedTv.setVisibility(View.VISIBLE); break; } } // 此方法直接照搬自網路上的一個下拉重新整理的demo，此處是“估計”headView的width以及height private void measureView(View child) { ViewGroup.LayoutParams params = child.getLayoutParams(); if (params == null) { params = new ViewGroup.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); } int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0 + 0, params.width); int lpHeight = params.height; int childHeightSpec; if (lpHeight > 0) { childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); } else { childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); } child.measure(childWidthSpec, childHeightSpec); } public void setonRefreshListener(OnRefreshListener refreshListener) { this.refreshListener = refreshListener; isRefreshable = true; } public interface OnRefreshListener { public void onRefresh(); } public void onRefreshComplete() { state = DONE; lvHeaderLastUpdatedTv.setText("最近更新:" + new Date().toLocaleString()); changeHeaderViewByState(); } private void onLvRefresh() { if (refreshListener != null) { refreshListener.onRefresh(); } } public void setAdapter(LvAdapter adapter) { lvHeaderLastUpdatedTv.setText("最近更新:" + new Date().toLocaleString()); super.setAdapter(adapter); } }
重寫完ListView之後，在佈局檔案中是這麼使用的，頭部下拉重新整理的佈局檔案lv_header.xml程式碼如下：
<?xml version="1.0" encoding="utf-8"?> <!-- ListView的頭部 --> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:background="#000000" > <!-- 內容 --> <RelativeLayout android:id="@+id/head_contentLayout" android:layout_width="fill_parent" android:layout_height="wrap_content" android:paddingLeft="30dp" > <!-- 箭頭影象、進度條 --> <FrameLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_centerVertical="true" > <!-- 箭頭 --> <ImageView android:id="@+id/lvHeaderArrowIv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:src="@drawable/arrow" /> <!-- 進度條 --> <ProgressBar android:id="@+id/lvHeaderProgressBar" style="?android:attr/progressBarStyleSmall" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:visibility="gone" /> </FrameLayout> <!-- 提示、最近更新 --> <LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:gravity="center_horizontal" android:orientation="vertical" > <!-- 提示 --> <TextView android:id="@+id/lvHeaderTipsTv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="下拉重新整理" android:textColor="@color/white" android:textSize="20sp" /> <!-- 最近更新 --> <TextView android:id="@+id/lvHeaderLastUpdatedTv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="上次更新" android:textColor="@color/gold" android:textSize="10sp" /> </LinearLayout> </RelativeLayout> </LinearLayout>
在Main.xml中進行設定，程式碼如下：
然後就是在MainActivity中實現，程式碼如下：<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="#000000" android:orientation="vertical" > <net.loonggg.listview.MyListView android:id="@+id/lv" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </LinearLayout>
package net.loonggg.listview;
import java.util.ArrayList;
import java.util.List;
import net.loonggg.listview.MyListView.OnRefreshListener;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends Activity {
private List<String> list;
private MyListView lv;
private LvAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv = (MyListView) findViewById(R.id.lv);
list = new ArrayList<String>();
list.add("loonggg");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
list.add("我們都是開發者");
adapter = new LvAdapter(list, this);
lv.setAdapter(adapter);
lv.setonRefreshListener(new OnRefreshListener() {
@Override
public void onRefresh() {
new AsyncTask<Void, Void, Void>() {
protected Void doInBackground(Void... params) {
try {
Thread.sleep(1000);
} catch (Exception e) {
e.printStackTrace();
}
list.add("重新整理後新增的內容");
return null;
}
@Override
protected void onPostExecute(Void result) {
adapter.notifyDataSetChanged();
lv.onRefreshComplete();
}
}.execute(null, null, null);
}
});
}
}
這裡還需要為ListView設定一下Adapter,自定義的Adapter如下：
package net.loonggg.listview;
import java.util.List;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
public class LvAdapter extends BaseAdapter {
private List<String> list;
private Context context;
public LvAdapter(List<String> list, Context context) {
this.list = list;
this.context = context;
}
@Override
public int getCount() {
return list.size();
}
@Override
public Object getItem(int position) {
return list.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
TextView tv = new TextView(context.getApplicationContext());
tv.setText(list.get(position));
return tv;
}
}
到這裡就完了，程式碼中的解釋非常詳細，具體的我就不多說了，也不解釋了，自己看看並研究吧！
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