检测到连接变化时更改 ListView 中随机项目的颜色

Question

我有一个接收连接变化的广播接收器broadcast.So只要连接变化是就会触发它detected.I有一个包含 10 个项目的列表视图items.Each有一个包含位置的 EditText该特定项目从 0 到 9。收到广播时，会生成一个从 0 到 9 的随机数，根据生成的随机数，我想更改相应文本视图中文本的颜色。如何实施？

我当前的代码是：

Manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.app.prateek.listviewbroadcastreceiver">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <receiver
            android:name=".MyReceiver"
            android:enabled="true"
            android:exported="true">
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
            </intent-filter>
        </receiver>
    </application>

</manifest>

MyReceiver.java

package com.app.prateek.listviewbroadcastreceiver;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;

import java.util.Random;

public class MyReceiver extends BroadcastReceiver {
    public MyReceiver() {
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO: This method is called when the BroadcastReceiver is receiving
        // an Intent broadcast.

        int min = 0;
        int max = 9;

        Random r = new Random();
        int highlight = r.nextInt(max - min + 1) + min;
        Toast.makeText(context, ""+highlight, Toast.LENGTH_SHORT).show();

        //change color of that particular object with generated random ID in listview
    }
}

MainActivity.java

package com.app.prateek.listviewbroadcastreceiver;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ListView;

public class MainActivity extends AppCompatActivity {

    ListView listView;
    IdAdapter idAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.listView);
        idAdapter=new IdAdapter(getApplicationContext(),R.layout.row_layout);
        listView.setAdapter(idAdapter);
        for(int i=0;i<10;i++)
        {
            idAdapter.add(new Id(i));
        }
    }
}

IdAdapter.java

package com.app.prateek.listviewbroadcastreceiver;

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.EditText;

import java.util.ArrayList;
import java.util.List;



public class IdAdapter extends ArrayAdapter {
    List list = new ArrayList();

    public IdAdapter(Context context, int resource) {
        super(context, resource);
    }

    @Override
    public void add(Object object) {
        super.add(object);
        list.add(object);
    }

    @Override
    public int getCount() {
        return list.size();
    }

    @Nullable
    @Override
    public Object getItem(int position) {
        return list.get(position);
    }

    @NonNull
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View row;
        row = convertView;
        DataHandlerRow dataHandlerRow;
        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row = inflater.inflate(R.layout.row_layout, parent, false);
            dataHandlerRow = new DataHandlerRow();
            dataHandlerRow.editTextId = (EditText) row.findViewById(R.id.editTextId);
            row.setTag(dataHandlerRow);
        } else {

            dataHandlerRow = (DataHandlerRow) row.getTag();

        }
        Id id = (Id) this.getItem(position);
        dataHandlerRow.editTextId.setText(id.getId() + "");
        return row;
    }

    static class DataHandlerRow {
        EditText editTextId;
    }
}

Id.java

public class Id {
    private int id;

    public Id(int id) {
        this.id = id;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }
}

row_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <EditText
        android:id="@+id/editTextId"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="1"
        android:textColor="@color/colorAccent"
        android:layout_centerHorizontal="true"
        android:textSize="20dp"/>

</RelativeLayout>

Answer 1

对于初学者来说，如果你想使用普通适配器，你应该实现赞助视图持有者 View holder pattern。

要执行您想要的操作，您只需在适配器中实现颜色，与实现的对象的属性相同。

Ejample（颜色可以作为字符串或应用程序资源传递）

public class Id {
    private int id;
    private String  color;

    public setColor(String color)
    {
    this.color= color;
    }
    public getColor()
    {
     return color;
    }
    public Id(int id) {
        this.id = id;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }
}

一旦你有了属性，你只需要从你的列表中选择适配器的相应元素，输入你想要的颜色并通知你适配器的更改

示例

((Iadapter)listview.getAdapter()).list.get(position_random).setColor("#ffa500");
((Iadapter)listview.getAdapter()).notifydatasetchanged();

在你的适配器中

 dataHandlerRow.editTextId.setTextColor(Color.parseColor(id.getColor()));

这对你有用，希望对你有所帮助

问候

Answer 2

制作一个新的适配器并使用侦听器回调模式将其设置在您的列表视图中

检测到连接变化时更改 ListView 中随机项目的颜色

Change color of an random item in ListView when connectivity change is detected

android

listview

design-patterns

android-broadcastreceiver