Android 自定義View - 網絡加載 ProgressBar 加載與隱藏

在Android App 開發中需要進行頻繁的網絡訪問，在不同的業務邏輯以及頁面中需要頻繁的生成 ProgressBar 來進行調用與展示，想想就是一件麻煩的事情…

來一波圖 ：

start

show

hide

SO  我們需要做的是：
1.創建一個BaseActivity讓之後的Activity繼承此Activity
2.自定義一個簡單的View用於顯示我們需要的ProgressBar 
3.將自定義View 加載到BaseActivity中設置顯示與隱藏方法
4.進行簡單的網絡訪問

step 1: 創建BaseActivity

package com.key.blog.base;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;

/**
 * created by key  on 2019/5/16
 */
public abstract class BaseActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        initView();
        initData();
    }
    
    
    public abstract void initView();
    public abstract void initData();
}

emmm… 新建一個抽象類BaseActivity 定義兩個抽象方法將頁面加載以及數據展示交由子類處理。

step2: 自定義View

1）.引用一個第三方ProgressBar庫，項目地址添加鏈接描述

implementation 'me.zhanghai.android.materialprogressbar:library:1.4.2'

2. 自定義BGProgressBar類

package com.key.blog.widget;

import android.content.Context;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;
import android.widget.LinearLayout;
import com.key.blog.R;

import me.zhanghai.android.materialprogressbar.MaterialProgressBar;

/**
 * created by key  on 2019/5/16
 */
public class BGProgressBar extends LinearLayout {
    private Context context;
    private AttributeSet attrs;
    private int defStyleAttr;

    private MaterialProgressBar materialProgressBar;

    public BGProgressBar(Context context) {
        super(context);
        this.context = context;
        init();
    }

    public BGProgressBar(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        this.context = context;
        this.attrs = attrs;
        init();
    }

    public BGProgressBar(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        this.context = context;
        this.attrs = attrs;
        this.defStyleAttr = defStyleAttr;
        init();
    }

    public void init(){
        View inflate = inflate(context, R.layout.item_progress_bar, this);
        materialProgressBar = inflate.findViewById(R.id.dynamic_progress);
    }


}

自定義View繼承自LinearLayout 重寫3個構造方法並加載佈局

3）自定義BGProgressBar佈局文件

item_progress_bar.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:background="@color/progress_dialog_root_bg"
    xmlns:app="http://schemas.android.com/apk/res-auto">


    <LinearLayout
        android:id="@+id/base"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/progress_bar_bg"
        android:gravity="center">

        <me.zhanghai.android.materialprogressbar.MaterialProgressBar
            android:paddingTop="3dp"
            android:paddingBottom="3dp"
            android:paddingLeft="5dp"
            android:paddingRight="5dp"
            android:layout_gravity="center"
            android:id="@+id/dynamic_progress"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:indeterminate="true"
            app:mpb_progressStyle="circular"
            app:mpb_indeterminateTint="@color/blue"
            style="@style/Widget.MaterialProgressBar.ProgressBar" />

    </LinearLayout>
</LinearLayout>

資源文件

color.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#008577</color>
    <color name="colorPrimaryDark">#00574B</color>
    <color name="colorAccent">#D81B60</color>
    <color name="progress_dialog_bg">#99000000</color>
    <color name="progress_dialog_root_bg">#00FFFFFF</color>
</resources>

drawable文件下 的 progress_bar_bg.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <solid android:color="@color/progress_dialog_bg"/>
    <corners android:radius="5dp"/>
</shape>

自定義View的佈局文件 在根佈局中設置寬高充滿整個佈局，並將其居中顯示

step3: 將自定義View綁定到BaseActivity

package com.key.blog.base;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;

import com.key.blog.widget.BGProgressBar;

/**
 * created by key  on 2019/5/16
 */
public abstract class BaseActivity extends AppCompatActivity {
    private BGProgressBar mBGProgressBar;
    private ViewGroup mRoot;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        initView();
        initData();
    }


    @Override
    protected void onStart() {
        super.onStart();
    }


    @Override
    protected void onResume() {
        super.onResume();
        mBGProgressBar = new BGProgressBar(this);
        mRoot = findViewById(android.R.id.content);
        mRoot.addView(mBGProgressBar);
        hide();
    }

    public abstract void initView();
    public abstract void initData();

    
    protected void show(){
        if( mBGProgressBar != null){
           if(mBGProgressBar.getVisibility() != View.VISIBLE){
                mBGProgressBar.setVisibility(View.VISIBLE);
            }
        }
    }


    protected void hide(){
        if( mBGProgressBar != null){
            mBGProgressBar.setVisibility(View.GONE);
        }
    }
}

在onResume方法中生成控件並添加到根佈局中設置初始狀態爲隱藏狀態
step4: try

創建一個Activity 繼承 BaseActivity 併發起網絡請求，請求用OKHttp 哦！！！！！！

OKHttp項目地址 添加鏈接描述

    implementation 'com.squareup.okhttp3:okhttp:3.12.1'
    implementation 'com.squareup.okio:okio:2.1.0'

package com.key.blog.page;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.key.blog.R;
import com.key.blog.base.BaseActivity;

import java.io.IOException;

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;



public class MainActivity extends BaseActivity {
    private Button try_bt;
    private TextView try_result;



    @SuppressLint("HandlerLeak")
    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what){
                case 0:
                    loadError();
                    break;
                case 1:
                    loadData();
                    break;
            }
        }
    };




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

    }

    @Override
    public void initView() {
        setContentView(R.layout.activity_main);
        try_bt = findViewById(R.id.try_bt);
        try_result = findViewById(R.id.try_result);
        try_bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                connectBaidu();
            }


        });
    }

    @Override
    public void initData() {

    }


    private void connectBaidu() {
        show();
        OkHttpClient okHttpClient = new OkHttpClient();
        Request request = new Request.Builder().url("https://www.baidu.com").build();
        Call call = okHttpClient.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                handler.sendEmptyMessage(0);
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                handler.sendEmptyMessageDelayed(1,2000);
            }
        });
    }



    private void loadError() {
        hide();
        try_result.setText("FAIL");
    }


    private void loadData() {
        hide();
        try_result.setText("SUCCESS");
    }


}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".page.MainActivity">



    <TextView
        android:id="@+id/try_result"
        android:paddingTop="50dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        android:text="RESULT"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/try_bt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TRY"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"/>
</android.support.constraint.ConstraintLayout>

國際慣例訪問通過okhttp訪問百度，延遲兩秒放送消息給主線程，我們只需要在顯示的地方調用show(),需要隱藏的地方調用hide().

打完睡覺。。。。。。兄弟們，輕噴。我只是一個剛畢業的菜鳥！！！！！
歡迎指出錯誤。