20221011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