Android listview数据显示及提示信息的实例
Android listview数据显示及提示信息的实例
最近我们测试人员说,我们的所有的列表都要做一个没有数据就提示没有数据,当时我的表情是这样的 =_=!!! 我的天呐……这么多列表真的要一个一个做嘛!!!然后我想了一下,那就直接改造Listview吧……说干就干。
没有数据的效果:
有数据的效果:
代码: NoDataListView.java
package com.tianjs.tianjinsuop2p.widgets; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Paint; import android.util.AttributeSet; import android.widget.Adapter; import android.widget.ListView; import com.tianjs.tianjinsuop2p.R; /** * Created by xiaolei on 2017/4/28. */ public class NoDataListView extends ListView { private int height = 0; private int width = 0; private Bitmap noDataBitmap = null; private Paint mPaint; private int minItem = 0; private int noDataImgInt = 0; public NoDataListView(Context context) { this(context, null); } public NoDataListView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public NoDataListView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.NoDataListView); noDataImgInt = array.getResourceId(R.styleable.NoDataListView_noDataImg, 0); minItem = array.getInt(R.styleable.NoDataListView_minItem, 0); if (noDataImgInt != 0) { noDataBitmap = BitmapFactory.decodeResource(getResources(), noDataImgInt); } else { noDataBitmap = Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888); } mPaint = new Paint(); array.recycle(); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { height = MeasureSpec.getSize(heightMeasureSpec); width = MeasureSpec.getSize(widthMeasureSpec); super.onMeasure(widthMeasureSpec, heightMeasureSpec); } @Override protected void onDraw(Canvas canvas) { Adapter adapter = getAdapter(); super.onDraw(canvas); if (adapter == null || adapter.getCount() <= minItem) { canvas.drawBitmap(noDataBitmap, width / 2 - noDataBitmap.getWidth() / 2, height / 2 - noDataBitmap.getHeight() / 2, mPaint); } } }
属性声明:
<declare-styleable name="NoDataListView"> <!--最低Item数--> <attr name="minItem" format="integer"/> <!--没有数据时,显示的图片资源--> <attr name="noDataImg" format="reference"/> </declare-styleable>
如何使用?
<com.tianjs.tianjinsuop2p.widgets.NoDataListView android:id="@+id/listview" android:layout_width="match_parent" android:layout_height="match_parent" android:divider="#00000000" android:dividerHeight="0dp" android:overScrollMode="never" android:scrollbars="none" app:minItem="0" app:noDataImg="@drawable/icon_wushuju"/>
其实就是在onDraw里面,检测到有几个item,如果adapter为null,或者adapter的count小于等于最小item数的话,就在背景显示没有数据的图片出来、
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