app/res/layout
中的activity_main.xml
文件的内容为以下内容:<?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=".MainActivity"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginEnd="80dp" android:layout_marginRight="80dp" android:text="HelloWorld!20175215 20175214 20175216" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintTop_toTopOf="parent" tools:text="HelloWorld!20175215 20175214 20175216" /> </android.support.constraint.ConstraintLayout>
- 运行结果以下图所示
MainActivity.class
中新加代码建立intent对象:package com.example.helloworld; import android.content.Intent; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Intent intent = new Intent(this,ThirdActivity.class); startActivity(intent); } }
activity_third.xml
的内容以下:<?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=".ThirdActivity"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginEnd="80dp" android:layout_marginRight="80dp" android:text="20175215丁文韬" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintTop_toTopOf="parent" tools:text="20175215丁文韬" /> </android.support.constraint.ConstraintLayout>
MainActivity.class
中新加代码后:package com.example.helloworld; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.widget.Toast; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Toast toast=Toast.makeText(MainActivity.this, "20175227丁文韬", Toast.LENGTH_LONG); toast.show(); } }
参考资料
布局的类型
- 线性布局LinearLayout:线性布局是一个视图组(ViewGroup),能在水平或者垂直的单一方向上将全部子元素排成一行
- 相对布局RelativeLayout:相对布局是一个将子视图显示在相对的位置上的布局
- 表格布局TableLayout:表格布局是在行、列中组合子元素的视图
- 绝对布局AbsoluteLayout:绝对布局能让你指定子元素的精确位置
- 帧布局FrameLayout:帧布局是一个屏幕上的占位符,你能够用它来显示单一视图
- 列表视图ListView:列表布局是能够滚动的,是用于显示子元素列表的视图组
- 网格视图GridView:网格视图是在二维可滚动的网格中显示子元素的视图组html
activity_main.xml
代码:<RelativeLayout 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" android:paddingLeft="2dp" android:paddingRight="2dp"> <Button android:id="@+id/cancelButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="20175215" android:layout_marginTop="70dp" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" /> <Button android:id="@+id/saveButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/cancelButton" android:layout_alignStart="@+id/cancelButton" android:layout_alignLeft="@+id/cancelButton" android:layout_marginStart="0dp" android:layout_marginLeft="0dp" android:layout_marginTop="119dp" android:text="丁文韬" /> <LinearLayout android:id="@+id/filter_button_container" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:gravity="center|bottom" android:background="@android:color/white" android:orientation="horizontal" > <Button android:id="@+id/filterButton" android:layout_width="wrap_content" android:layout_height="fill_parent" android:text="筛选" /> <Button android:id="@+id/shareButton" android:layout_width="wrap_content" android:layout_height="fill_parent" android:text="分享" /> <Button android:id="@+id/deleteButton" android:layout_width="wrap_content" android:layout_height="fill_parent" android:text="删除" /> </LinearLayout> <ImageButton android:id="@+id/imageButton" android:layout_width="212dp" android:layout_height="167dp" android:layout_alignParentBottom="true" android:layout_centerHorizontal="true" android:layout_marginBottom="160dp" app:srcCompat="@mipmap/ic_launcher" /> </RelativeLayout>
package com.example.helloworld; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.app.Activity; import android.graphics.Color; import android.os.Bundle; import android.view.Menu; import android.view.View; import android.widget.AnalogClock; import android.app.Activity; import android.graphics.Color; import android.os.Bundle; import android.view.Menu; import android.view.View; import android.widget.AnalogClock; public class MainActivity extends Activity { int counter = 0; int[] colors = { Color.BLACK, Color.BLUE, Color.CYAN, Color.DKGRAY, Color.GRAY, Color.GREEN, Color.LTGRAY, Color.MAGENTA, Color.RED, Color.WHITE, Color.YELLOW }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.menu_main, menu); return true; } public void changeColor(View view) { if (counter == colors.length) { counter = 0; } view.setBackgroundColor(colors[counter++]); } }
<?xml version="1.0" encoding="utf-8"?> <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"> <AnalogClock android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:layout_marginTop="90dp" android:id="@+id/analogClock1" android:onClick="changeColor" /> <TextView android:layout_width="match_parent" android:layout_height="match_parent" android:text="20175215丁文韬" android:layout_marginLeft="70dp" android:layout_marginTop="300dp" android:textSize="21dp"/> </RelativeLayout>
未等到下图部分加载完成,误认为是sdk等文件安装错误
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