view 状态检查

在实际开发中，可能会遇到这个需求： 如果界面有很多输入框，在点击返回的时候，没有输入过文字就不弹提示框，反之就弹框提示用户需要保存草稿吗？/确定退出吗？

如果给每一个view 设置 监听器想必代码会冗余很多， 也不易于维护， 那么就想到了这个办法，直接贴代码吧：

package com.******.library.utils;

import android.view.View;
import android.view.ViewGroup;
import android.widget.CompoundButton;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Set;

/**
 * Created by LiKang on 2017/4/7 18:53.
 * email：[email protected]
 */
public class ViewStateCheckUtil {

    private HashMap<Integer, BaseState> oldStates;
    private HashMap<Integer, BaseState> newStates;
    private View checkView;
    private String TAG = "ViewStateCheckUtil";

    //被忽略统计的view ID 集合
    private ArrayList<Integer> ignoreViewIds;

    public ViewStateCheckUtil(View checkView, ArrayList<Integer> ignoreViewIds) {
        this.checkView = checkView;
        this.ignoreViewIds = ignoreViewIds;
    }

    public ViewStateCheckUtil(View checkView) {
        this.checkView = checkView;
    }

    public void setCurrentState() {
        oldStates = getHierarchyState();
    }

    private List<View> getAllChildViews(View view) {

        List<View> allChildren = new ArrayList<>();

        if (ignoreViewIds != null && ignoreViewIds.contains(view.getId()))
            return allChildren;

        if (view instanceof ViewGroup) {
            ViewGroup vp = (ViewGroup) view;
            for (int i = 0; i < vp.getChildCount(); i++) {
                View viewChild = vp.getChildAt(i);

                allChildren.add(viewChild);
                allChildren.addAll(getAllChildViews(viewChild));
            }
        }
        return allChildren;
    }


    public HashMap<Integer, BaseState> getHierarchyState() {
        HashMap<Integer, BaseState> hierarchyState = new HashMap<>();
        if (checkView == null) return hierarchyState;
        if (checkView instanceof ViewGroup) {
            List<View> allChildViews = getAllChildViews(checkView);
            Logger.d(TAG, allChildViews.toString());
            Logger.d(TAG, "allChildViews.size():" + allChildViews.size());

            for (int i = 0; i < allChildViews.size(); i++) {
                addViewState(hierarchyState, allChildViews.get(i));
            }
        } else {
            addViewState(hierarchyState, checkView);
        }
        return hierarchyState;
    }

    private void addViewState(HashMap<Integer, BaseState> hierarchyState, View child) {

        if (child.getId() == View.NO_ID)
            return;

        if (child instanceof CompoundButton) { //CompoundButton 也是 TextView 子类
            CompoundButtonState state = new CompoundButtonState();
            CompoundButton compoundButton = (CompoundButton) child;
            state.setChecked(compoundButton.isChecked());
            hierarchyState.put(child.getId(), state);
        } else if (child instanceof TextView) {
            TextViewState state = new TextViewState();
            TextView textView = (TextView) child;
            state.setText(textView.getText().toString());
            hierarchyState.put(child.getId(), state);
        }

    }

    public Boolean checkViewIsChanged() {
        newStates = getHierarchyState();
        if (oldStates == null)
            return false;
        Logger.d("checkViewIsChanged,newStates", newStates.toString());
        Logger.d("checkViewIsChanged,oldStates", oldStates.toString());

        Set<Integer> newKeySet = newStates.keySet();
        Set<Integer> oldKeySet = oldStates.keySet();
        Set<Integer> keySet = newKeySet.size() > oldKeySet.size() ? newKeySet : oldKeySet;

        for (Integer viewId : keySet) {
            BaseState newState = newStates.get(viewId);
            BaseState oldState = oldStates.get(viewId);
            Logger.d(TAG, "newState:" + newState);
            Logger.d(TAG, "oldState:" + oldState);

            if (!(newState + "").equals(oldState + "")) {
                return true;
            }

        }
        return false;
    }


    private class BaseState {

    }

    private class TextViewState extends BaseState {

        String text;

        String getText() {
            return text;
        }

        void setText(String text) {
            this.text = text;
        }

        @Override
        public String toString() {
            return "TextViewState{" +
                    "text=" + text +
                    '}';
        }
    }


    private class CompoundButtonState extends BaseState {
        boolean checked;

        boolean isChecked() {
            return checked;
        }

        void setChecked(boolean checked) {
            this.checked = checked;
        }

        @Override
        public String toString() {
            return "CompoundButtonState{" +
                    "checked=" + checked +
                    '}';
        }
    }

    //TODO other view states supplement


}

如何使用？代码很简单， 可能你已经知道使用方式了。

    private ViewStateCheckUtil viewStateCheckUtil;

   @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        .....


        ArrayList<Integer> ignoreViewIds = new ArrayList<>();
        ignoreViewIds.add(lvVideo.getId());//设置要忽略的view ;

        viewStateCheckUtil = new ViewStateCheckUtil(mRootView, ignoreViewIds/*可以传null*/);
        viewStateCheckUtil.setCurrentState();//在这里保存要统计view的状态

}


    @Override
    public void onBackPressed() {
        finishNotify();

    }

    private void finishNotify() {
        if (viewStateCheckUtil.checkViewIsChanged()) {

          //弹框提示，是否要退出编辑

        } else {
            finish();
        }
    }

好了，到此结束了。。。