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法律研究如何在 RecycleView 中使用約束佈局？
該示例演示瞭如何在 RecycleView 中使用約束佈局
步驟 1 − 在 Android Studio 中建立新專案，轉到檔案 ⇒ 新專案，並填寫所有必需資訊以建立新專案。
步驟 2 − 向 res/layout/activity_main.xml 中新增以下程式碼。
<?xml version = "1.0" encoding = "utf-8"?> <android.support.design.widget.CoordinatorLayout android:layout_width = "match_parent" android:layout_height = "match_parent" xmlns:android = "http://schemas.android.com/apk/res/android" xmlns:app = "http://schemas.android.com/apk/res-auto"> <android.support.design.widget.AppBarLayout android:layout_width = "match_parent" android:layout_height = "wrap_content"> <android.support.v7.widget.Toolbar android:id = "@+id/appbarlayout_tool_bar" android:background = "@color/colorPrimary" android:layout_width = "match_parent" android:layout_height = "?attr/actionBarSize" app:layout_scrollFlags = "scroll|snap|enterAlways" app:theme = "@style/ThemeOverlay.AppCompat.Dark.ActionBar" app:popupTheme = "@style/ThemeOverlay.AppCompat.Light" /> </android.support.design.widget.AppBarLayout> <android.support.v7.widget.RecyclerView android:id = "@+id/recycler_view" android:layout_width = "match_parent" android:layout_height = "match_parent" app:layout_behavior = "@string/appbar_scrolling_view_behavior"/> </android.support.design.widget.CoordinatorLayout>
在上述程式碼中，我們使用了應用欄佈局和回收器檢視。
步驟 3 − 向 src/MainActivity.java 中新增以下程式碼
<?xml version = "1.0" encoding = "utf-8"?>
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.content.pm.ShortcutInfoCompat;
import android.support.v4.content.pm.ShortcutManagerCompat;
import android.support.v4.graphics.drawable.IconCompat;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.DividerItemDecoration;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import android.support.v7.widget.Toolbar;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private RecyclerView recyclerView;
private customAdapter mAdapter;
TextView text;
ArrayList<String> list = new ArrayList<>();
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (android.support.v7.widget.Toolbar)findViewById(R.id.appbarlayout_tool_bar);
toolbar.setTitle("This is toolbar.");
setSupportActionBar(toolbar);
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
mAdapter = new customAdapter(this,list);
recyclerView.setAdapter(mAdapter);
recyclerView.addItemDecoration(new DividerItemDecoration(recyclerView.getContext(), DividerItemDecoration.VERTICAL));
list.add("sairamm");
list.add("Krishna");
list.add("prasad");
list.add("sairamm");
list.add("Krishna");
list.add("prasad");
list.add("sairamm");
list.add("Krishna");
list.add("prasad");
list.add("sairamm");
list.add("Krishna");
list.add("prasad");
list.add("Krishna");
list.add("prasad");
list.add("sairamm");
list.add("Krishna");
list.add("prasad");
list.add("sairamm");
list.add("Krishna");
list.add("prasad");
}
}步驟 4 − 向 Manifest.xml 中新增以下程式碼
<?xml version = "1.0" encoding = "utf-8"?> <manifest xmlns:android = "http://schemas.android.com/apk/res/android" package = "com.example.myapplication"> <uses-permission android:name = "android.permission.INTERNET" /> <uses-permission android:name = "com.android.launcher.permission.INSTALL_SHORTCUT" /> <application android:allowBackup = "true" android:theme = "@style/AppTheme.NoActionBar" android:icon = "@mipmap/ic_launcher" android:label = "@string/app_name" android:roundIcon = "@mipmap/ic_launcher_round" android:supportsRtl = "true"> <activity android:name = ".MainActivity" android:configChanges = "keyboardHidden|orientation|screenSize"> <intent-filter> <action android:name = "android.intent.action.MAIN" /> <action android:name = "android.intent.action.CREATE_SHORTCUT" /> <category android:name = "android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
步驟 5 − 向 customAdapter.java 中新增以下程式碼
<?xml version = "1.0" encoding = "utf-8"?>
import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
public class customAdapter extends RecyclerView.Adapter<customAdapter.MyViewHolder> {
Context context;
ArrayList<String> list;
public class MyViewHolder extends RecyclerView.ViewHolder {
public TextView title;
public MyViewHolder(View view) {
super(view);
title = (TextView) view.findViewById(R.id.title);
}
}
public customAdapter(Context context, ArrayList<String> list) {
this.context = context;
this.list = list;
}
@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
View itemView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.list_row, viewGroup, false);
return new MyViewHolder(itemView);
}
@Override
public void onBindViewHolder(@NonNull MyViewHolder myViewHolder, int i) {
myViewHolder.title.setText(list.get(i));
}
@Override
public int getItemCount() {
return list.size();
}
}步驟 6 − 向 list_row.xml 中新增以下程式碼
<?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 = "wrap_content" android:background = "@color/colorAccent" tools:context = ".MainActivity"> <ImageView android:id = "@+id/imageView2" android:layout_width = "wrap_content" android:layout_height = "wrap_content" android:src = "@drawable/logo" app:layout_constraintBottom_toBottomOf = "parent" app:layout_constraintEnd_toEndOf = "parent" app:layout_constraintStart_toStartOf = "parent" app:layout_constraintTop_toTopOf = "parent" app:layout_constraintVertical_bias = "0.209" /> <TextView android:id = "@+id/title" android:layout_width = "match_parent" android:layout_height = "wrap_content" android:layout_marginTop = "35dp" android:gravity = "center" android:textSize = "30sp" app:layout_constraintTop_toBottomOf = "@+id/imageView2" tools:layout_editor_absoluteX = "0dp" /> <TextView android:id = "@+id/textview2" android:layout_width = "match_parent" android:layout_height = "wrap_content" android:layout_marginTop = "16dp" android:layout_marginBottom = "8dp" android:gravity = "center" android:text = "Sairamkrishan" android:textSize = "30sp" app:layout_constraintBottom_toBottomOf = "parent" app:layout_constraintTop_toBottomOf = "@+id/title" app:layout_constraintVertical_bias = "0.0" tools:layout_editor_absoluteX = "0dp" /> </android.support.constraint.ConstraintLayout>
我們來試執行一下你的應用程式。我假設你已經將你的實際 Android 移動裝置與你的計算機連線好了。要從 Android Studio 中執行應用，開啟你的一個專案活動檔案，並單擊工具欄中的執行 
圖示。選擇你的移動裝置作為選項，然後檢視你的移動裝置，上面將會顯示你的預設螢幕 –
更新於： 2019-07-30
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