Android ProgressBar（进度条）使用

例题2-10

activity_main.xml代码

<?xml version="1.0" encoding="utf-8"?>
<GridLayout android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:columnCount="4"
    android:rowCount="6"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <ProgressBar
        android:id="@+id/progressbar1"
        android:layout_width="650px"
        android:layout_height="wrap_content"
        android:max="200"
        android:progress="20"
        android:layout_columnSpan="4"
        style="@style/Widget.AppCompat.ProgressBar.Horizontal"
        >
    </ProgressBar>
    <Button
        android:id="@+id/but1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="减少"/>
    <Button
        android:id="@+id/but2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="增加"/>
</GridLayout>

Mainactivity.java代码

package com.example.hello;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;

public class MainActivity extends AppCompatActivity {
    Button but1;
    Button but2;
    ProgressBar pro;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        pro = (ProgressBar)findViewById(R.id.progressbar1);
        but1 = (Button)findViewById(R.id.but1);
        but2 = (Button)findViewById(R.id.but2);
        but1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                pro.incrementProgressBy(-10);
            }
        });
        but2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                pro.incrementProgressBy(10);
            }
        });
    }

}