这周一次来了两个课程，很激动啊，其实是累得tu啊。
主题 court counter
一. 目标
目标 篮球计分器
- 类似双栏的布局（两路linearl layout）(layout嵌套)
- 学习view style属性：gravity
- 界面优化技巧
- 一种功能对应一种颜色
- 温习变量作用域
- 全局变量记录比分
- 涉及篮球比赛规则
- 重置比分
二. 本轮 new concept
问题引出
- 除了整个布局的四个角（详细是buttom/top和left/right组合），还能不能在一个子视图里面移动（居中，靠左，靠右）。。。
solution
layout_gravity: 定位一个子视图应该在父视图的哪一块。
https://developer.android.com/intl/zh-cn/reference/android/widget/LinearLayout.LayoutParams.html#attr_android:layout_gravity
gravity: 定位内容应在对象的哪一块。
https://developer.android.com/intl/zh-cn/reference/android/widget/LinearLayout.html#attr_android:gravity
三 界面设计截图
待
代码过程
java代码
package com.example.android.courtcounter;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
/**
* This activity keeps track of the basketball score for 2 teams.
*/
public class MainActivity extends AppCompatActivity {
// Tracks the score for Team A
int scoreTeamA = 0;
// Tracks the score for Team B
int scoreTeamB = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String jamesbond = "hi";
String jamesBond = "hello";
String s = jamesBond + jamesbond;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimpSlifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* Increase the score for Team A by 1 point.
*/
public void addOneForTeamA(View v) {
scoreTeamA = scoreTeamA + 1;
displayForTeamA(scoreTeamA);
}
/**
* Increase the score for Team A by 2 points.
*/
public void addTwoForTeamA(View v) {
scoreTeamA = scoreTeamA + 2;
displayForTeamA(scoreTeamA);
}
/**
* Increase the score for Team A by 3 points.
*/
public void addThreeForTeamA(View v) {
scoreTeamA = scoreTeamA + 3;
displayForTeamA(scoreTeamA);
}
/**
* Increase the score for Team B by 1 point.
*/
public void addOneForTeamB(View v) {
scoreTeamB = scoreTeamB + 1;
displayForTeamB(scoreTeamB);
}
/**
* Increase the score for Team B by 2 points.
*/
public void addTwoForTeamB(View v) {
scoreTeamB = scoreTeamB + 2;
displayForTeamB(scoreTeamB);
}
/**
* Increase the score for Team B by 3 points.
*/
public void addThreeForTeamB(View v) {
scoreTeamB = scoreTeamB + 3;
displayForTeamB(scoreTeamB);
}
/**
* Resets the score for both teams back to 0.
*/
public void resetScore(View v) {
scoreTeamA = 0;
scoreTeamB = 0;
displayForTeamA(scoreTeamA);
displayForTeamB(scoreTeamB);
}
/**
* Displays the given score for Team A.
*/
public void displayForTeamA(int score) {
TextView scoreView = (TextView) findViewById(R.id.team_a_score);
scoreView.setText(String.valueOf(score));
}
/**
* Displays the given score for Team B.
*/
public void displayForTeamB(int score) {
TextView scoreView = (TextView) findViewById(R.id.team_b_score);
scoreView.setText(String.valueOf(score));
}
}
layout
再额外的布局上，我加上了图片，自己添加了drawable文件夹
<?xml version="1.0" encoding="utf-8"?>
<!-- Layout for the basketball score counter. -->
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical">
<ImageView
android:layout_width="120dp"
android:layout_height="120dp"
android:gravity="center"
android:src="@drawable/i1"
android:layout_gravity="center_horizontal" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-medium"
android:gravity="center"
android:padding="16dp"
android:text="Team A"
android:textColor="#616161"
android:textSize="14sp" />
<TextView
android:id="@+id/team_a_score"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-light"
android:gravity="center"
android:paddingBottom="24dp"
android:text="0"
android:textColor="#000000"
android:textSize="56sp" />
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="addThreeForTeamA"
android:text="+3 Points" />
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="addTwoForTeamA"
android:text="+2 Points" />
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="addOneForTeamA"
android:text="Free throw" />
</LinearLayout>
<View
android:layout_width="1dp"
android:layout_height="match_parent"
android:layout_marginTop="16dp"
android:background="@android:color/darker_gray" />
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="vertical">
<ImageView
android:layout_width="120dp"
android:layout_height="120dp"
android:gravity="center"
android:src="@drawable/i3"
android:layout_gravity="center_horizontal" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-medium"
android:gravity="center"
android:padding="16dp"
android:text="Team B"
android:textColor="#616161"
android:textSize="14sp" />
<TextView
android:id="@+id/team_b_score"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="sans-serif-light"
android:gravity="center"
android:paddingBottom="24dp"
android:text="0"
android:textColor="#000000"
android:textSize="56sp" />
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginLeft="24dp"
android:layout_marginRight="24dp"
android:onClick="addThreeForTeamB"
android:text="+3 Points" />
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginLeft="22dp"
android:layout_marginRight="22dp"
android:onClick="addTwoForTeamB"
android:text="+2 Points" />
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginLeft="22dp"
android:layout_marginRight="22dp"
android:onClick="addOneForTeamB"
android:text="Free throw" />
</LinearLayout>
</LinearLayout>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="32dp"
android:onClick="resetScore"
android:text="Reset" />
</RelativeLayout>四. tips
- 先写Java的方法，后写XML，可以自动提示
- 第一次见到两个竖直并列的linear layout
- 升级AS后，styles.xml要注意以下细节往Theme之前加Base(如果Theme没有),不然会报The following classes could not be instantiated
android.support.v7.internal.widget.ActionBarOverlayLayout
<style name="AppTheme" parent="Base.Theme.AppCompat.Light">五.后话
这是第一次在真机note 2上录制，
首先录制后是横屏的，
其次adb shell screencapture 在我的android 4.3上命令不能用
android studio也不支持录制。
一共耗了3个小时找了各种工具搞定，要有一个好的demo不容易啊！
代码时间一半
录屏时间大半。。。
六.参考
bug： The following classes could not be instantiated
mp4转gif
感谢 昵图网图标
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