Android通用LoadingView加载框架详解

手写一个通用加载中、显示数据、加载失败、空数据的LoadingView框架。

定义3个布局：加载中，加载失败，空数据

加载中:

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:background="#ffffff"
 android:clickable="true">

 <ProgressBar
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_gravity="center"
  android:indeterminate="true" />

</FrameLayout>

加载失败:

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:background="#ffffff"
 android:clickable="true"
 android:orientation="vertical">

 <ImageView
  android:id="@+id/error_retry"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_gravity="center"
  android:gravity="center"
  android:src="@drawable/loading_retry" />

</FrameLayout>

空数据:

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:background="#ffffff"
 android:clickable="true"
 android:orientation="vertical">

 <ImageView
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_gravity="center"
  android:src="@drawable/loading_empty" />

</FrameLayout>

自定义一个LoadingView:

package com.sample.loadingview.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.support.annotation.AttrRes;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.util.SparseArray;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.ImageView;

import com.sample.loadingview.R;

public class LoadingView extends FrameLayout {
 private int emptyLayoutId, errorLayoutId, loadingLayoutId;
 private View contentView, emptyView, errorView, loadingView;
 private LayoutInflater mInflater;
 private SparseArray<View> views = new SparseArray<>();

 public LoadingView(@NonNull Context context) {
  this(context, null);
 }

 public LoadingView(@NonNull Context context, @Nullable AttributeSet attrs) {
  this(context, attrs, 0);
 }

 public LoadingView(@NonNull Context context, @Nullable AttributeSet attrs, @AttrRes int defStyleAttr) {
  super(context, attrs, defStyleAttr);

  TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.LoadLayout);
  emptyLayoutId = a.getResourceId(R.styleable.LoadLayout_emptyView, R.layout.loading_empty);
  errorLayoutId = a.getResourceId(R.styleable.LoadLayout_errorView, R.layout.loading_error);
  loadingLayoutId = a.getResourceId(R.styleable.LoadLayout_loadingView, R.layout.loading_load);
  mInflater = LayoutInflater.from(getContext());
  a.recycle();
  loadingView = mInflater.inflate(loadingLayoutId, null);
 }

 @Override
 protected void onFinishInflate() {
  super.onFinishInflate();
  if (getChildCount() < 1) {
   throw new RuntimeException("content view can not be null");
  }
  contentView = getChildAt(0);

  if (loadingView.getVisibility() != GONE)
   loadingView.setVisibility(GONE);
  addView(loadingView);
  views.put(loadingLayoutId, loadingView);
 }

 public void showError() {
  errorView = views.get(errorLayoutId);
  if (errorView == null) {
   errorView = mInflater.inflate(errorLayoutId, null);
   addView(errorView);
   views.put(errorLayoutId, errorView);
   final ImageView errorRetry = (ImageView) errorView.findViewById(R.id.error_retry);
   errorRetry.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
     if (mOnRetryClickListener != null)
      mOnRetryClickListener.onClick(errorRetry);
    }
   });
  }
  if (errorView.getVisibility() != VISIBLE)
   errorView.setVisibility(VISIBLE);

  for (int i = 0, len = views.size(); i < len; i++) {
   int key = views.keyAt(i);
   if (key != errorLayoutId) {
    View view = views.valueAt(i);
    if (view != null)
     if (view.getVisibility() != GONE)
      view.setVisibility(GONE);
   }
  }
 }

 public void showEmpty() {
  emptyView = views.get(emptyLayoutId);
  if (emptyView == null) {
   emptyView = mInflater.inflate(emptyLayoutId, null);
   addView(emptyView);
   views.put(emptyLayoutId, emptyView);
  }
  if (emptyView.getVisibility() != VISIBLE)
   emptyView.setVisibility(VISIBLE);

  for (int i = 0, len = views.size(); i < len; i++) {
   int key = views.keyAt(i);
   if (key != emptyLayoutId) {
    View view = views.valueAt(i);
    if (view != null)
     if (view.getVisibility() != GONE)
      view.setVisibility(GONE);
   }
  }
 }

 public void showLoading() {
  loadingView = views.get(loadingLayoutId);
  if (loadingView.getVisibility() != VISIBLE)
   loadingView.setVisibility(VISIBLE);

  for (int i = 0, len = views.size(); i < len; i++) {
   int key = views.keyAt(i);
   if (key != loadingLayoutId) {
    View view = views.valueAt(i);
    if (view != null)
     if (view.getVisibility() != GONE)
      view.setVisibility(GONE);
   }
  }
 }

 public void showContent() {
  for (int i = 0, len = views.size(); i < len; i++) {
   View view = views.valueAt(i);
   if (view != null)
    if (view.getVisibility() != GONE)
     view.setVisibility(GONE);
  }
 }

 private OnClickListener mOnRetryClickListener;

 public void setOnRetryClickListener(OnClickListener onRetryClickListener) {
  this.mOnRetryClickListener = onRetryClickListener;
 }
}

定义attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <declare-styleable name="LoadLayout">
  <attr name="loadingView" format="reference" />
  <attr name="errorView" format="reference" />
  <attr name="retryView" format="reference" />
  <attr name="emptyView" format="reference" />
 </declare-styleable>
</resources>

以上就这么些代码，接下来我们测试一下

Activity

package com.sample.loadingview;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import com.sample.loadingview.widget.LoadingView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

 private LoadingView loading_view;
 private Button btn_loading;
 private Button btn_content;
 private Button btn_error;
 private Button btn_empty;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  loading_view = (LoadingView) findViewById(R.id.loading_view);
  btn_loading = (Button) findViewById(R.id.btn_loading);
  btn_content = (Button) findViewById(R.id.btn_content);
  btn_error = (Button) findViewById(R.id.btn_error);
  btn_empty = (Button) findViewById(R.id.btn_empty);

  //设置加载错误的点击事件
  loading_view.setOnRetryClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    Toast.makeText(MainActivity.this, "重新加载", Toast.LENGTH_SHORT).show();
    loading_view.showLoading();
   }
  });
  btn_loading.setOnClickListener(this);
  btn_content.setOnClickListener(this);
  btn_error.setOnClickListener(this);
  btn_empty.setOnClickListener(this);
 }

 @Override
 public void onClick(View v) {
  switch (v.getId()) {
   case R.id.btn_loading:
    loading_view.showLoading();//显示加载界面
    break;
   case R.id.btn_content:
    loading_view.showContent();//显示内容界面
    break;
   case R.id.btn_error:
    loading_view.showError();//显示错误界面
    break;
   case R.id.btn_empty:
    loading_view.showEmpty();//显示空数据界面
    break;
  }
 }
}

源码：下载地址

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