2022-10-11学习内容

1.Button

1.1activity_button_view.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:orientation="vertical"
    android:padding="5dp">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="下面的按钮英文默认大写"
        android:textColor="@color/black"
        android:textSize="17sp" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Hello World"
        android:textColor="@color/black"
        android:textSize="17sp" />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="下面的按钮英文保持原状"
        android:textColor="@color/black"
        android:textSize="17sp" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Hello World"
        android:textAllCaps="false"
        android:textColor="@color/black"
        android:textSize="17sp" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="直接指定点击方法"
        android:textAllCaps="false"
        android:textColor="@color/black"
        android:textSize="17sp"
        android:onClick="doClick"/>

    <TextView
        android:id="@+id/tv_result"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="这里查看按钮的点击结果"
        android:textColor="@color/black"
        android:textSize="17sp" />

</LinearLayout>

1.2ButtonStyleActivity.java

package com.example.chapter03;

import androidx.appcompat.app.AppCompatActivity;

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

import com.example.chapter03.utils.DateUtil;

public class ButtonStyleActivity extends AppCompatActivity {

    // 快捷键 ctrl+alt+f 把onCreate方法中的局部变量提取成全局的属性
    private TextView tv_result;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_button_style);
        tv_result = findViewById(R.id.tv_result);
    }

    public void doClick(View view) {
        String desc = String.format("%s 您点击了按钮； %s", DateUtil.getNowTime(), ((Button)view).getText());
        tv_result.setText(desc);
    }
}

1.3DateUtil.java

package com.example.chapter03.utils;

import java.text.SimpleDateFormat;
import java.util.Date;

public class DateUtil {

    public static String getNowTime() {
        SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
        return sdf.format(new Date());
    }
}

1.4效果

2.点击事件

2.1activity_button_click.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:orientation="vertical">

    <Button
        android:id="@+id/btn_click_single"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="指定单独的点击监听器"
        android:textColor="#000000"
        android:textSize="15sp" />

    <TextView
        android:id="@+id/tv_result"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="5dp"
        android:gravity="center"
        android:textColor="#000000"
        android:textSize="15sp"
        android:text="这里查看按钮的点击结果"/>

</LinearLayout>

2.2ButtonClickActivity.java

package com.example.chapter03;

import androidx.appcompat.app.AppCompatActivity;

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

import com.example.chapter03.utils.DateUtil;

public class ButtonClickActivity extends AppCompatActivity {

    // ctrl+alt+f
    private TextView tv_result;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_button_click);
        tv_result = findViewById(R.id.tv_result);
        Button btn_click_single = findViewById(R.id.btn_click_single);
        btn_click_single.setOnClickListener(new MyViewOnClickListener(tv_result));
    }

    static class MyViewOnClickListener implements View.OnClickListener {
        private final TextView tv_result;
        public MyViewOnClickListener(TextView tv_result) {
            this.tv_result = tv_result;
        }
        @Override
        public void onClick(View v) {
            String desc = String.format("%s 您点击了按钮； %s", DateUtil.getNowTime(), ((Button)v).getText());
            tv_result.setText(desc);
        }
    }
}

2.3效果

 

2.4activity_button_click.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:orientation="vertical">

    <Button
        android:id="@+id/btn_click_single"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="指定单独的点击监听器"
        android:textColor="#000000"
        android:textSize="15sp" />

    <Button
        android:id="@+id/btn_click_public"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="指定公共的点击监听器"
        android:textColor="#000000"
        android:textSize="15sp" />

    <TextView
        android:id="@+id/tv_result"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="5dp"
        android:gravity="center"
        android:textColor="#000000"
        android:textSize="15sp"
        android:text="这里查看按钮的点击结果"/>

</LinearLayout>

2.5ButtonClickActivity.java

package com.example.chapter03;

import androidx.appcompat.app.AppCompatActivity;

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

import com.example.chapter03.utils.DateUtil;

public class ButtonClickActivity extends AppCompatActivity implements View.OnClickListener {

    // ctrl+alt+f
    private TextView tv_result;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_button_click);
        tv_result = findViewById(R.id.tv_result);
        Button btn_click_single = findViewById(R.id.btn_click_single);
        btn_click_single.setOnClickListener(new MyViewOnClickListener(tv_result));

        Button btn_click_public = findViewById(R.id.btn_click_public);
        btn_click_public.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.btn_click_public) {
            String desc = String.format("%s 您点击了按钮； %s", DateUtil.getNowTime(), ((Button)v).getText());
            tv_result.setText(desc);
        }
    }

    static class MyViewOnClickListener implements View.OnClickListener {
        private final TextView tv_result;
        public MyViewOnClickListener(TextView tv_result) {
            this.tv_result = tv_result;
        }
        @Override
        public void onClick(View v) {
            String desc = String.format("%s 您点击了按钮； %s", DateUtil.getNowTime(), ((Button)v).getText());
            tv_result.setText(desc);
        }
    }
}

2.6效果