android 自定义列表视图实现

Question

基本上，android 列表视图 activity 是透明的，我已经设法使用自定义布局将其设为纯黑色，但我如何使其像第三张图片一样，角颜色是随机的.

提前致谢

MainActivity.java

import android.app.Activity;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.TranslateAnimation;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RelativeLayout;
import android.widget.ArrayAdapter;

public class MainActivity extends Activity {

// Declare
private LinearLayout slidingPanel;
private boolean isExpanded;
private DisplayMetrics metrics;
private RelativeLayout headerPanel;
private int panelWidth;
private int panelWidth1;


private ImageView menuViewButton,menuRightButton;

FrameLayout.LayoutParams menuPanelParameters;
FrameLayout.LayoutParams slidingPanelParameters;
LinearLayout.LayoutParams headerPanelParameters;
LinearLayout.LayoutParams listViewParameters;

//Example
////////
String[] Example = new String[]
        { "Android Introduction","Android Setup/Installation","Android Hello World",
                "Android Layouts/Viewgroups","Android Activity & Lifecycle","Intents in Android"};


////////
//Example
@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_layer_stack);

    // Initialize
    metrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(metrics);
    panelWidth = (int) ((metrics.widthPixels) * -0.65);//Right panel width
    panelWidth1 = (int) ((metrics.widthPixels) * 0.65);//left panel width

    headerPanel = (RelativeLayout) findViewById(R.id.header);
    headerPanelParameters = (LinearLayout.LayoutParams) headerPanel
            .getLayoutParams();
    headerPanelParameters.width = metrics.widthPixels;
    headerPanel.setLayoutParams(headerPanelParameters);

    slidingPanel = (LinearLayout) findViewById(R.id.slidingPanel);
    slidingPanelParameters = (FrameLayout.LayoutParams) slidingPanel
            .getLayoutParams();
    slidingPanelParameters.width = metrics.widthPixels;
    slidingPanel.setLayoutParams(slidingPanelParameters);
    ///////

    ArrayAdapter<String> ExampleArrayAdapter = new CustomAdapter(this, Example);
    //changing code//practice
    /*new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,
            Example);*/
    ListView ExampleListView = (ListView)findViewById(R.id.listView);
    ExampleListView.setAdapter(ExampleArrayAdapter);
    ///////

    // Slide the Panel
    menuRightButton = (ImageView) findViewById(R.id.menuViewButton);
    menuRightButton.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            if (!isExpanded) {
                isExpanded = true;
                // Expand

                FragmentManager fragmentManager = getFragmentManager();

                FragmentTransaction fragmentTransaction = fragmentManager
                        .beginTransaction();
                fragmentTransaction.replace(R.id.menuPanel,
                        new LeftMenuFragment());
                fragmentTransaction.commit();
                new ExpandAnimation(slidingPanel, panelWidth1,
                        Animation.RELATIVE_TO_SELF, 0.0f,
                        Animation.RELATIVE_TO_SELF, 0.65f, 0, 0.0f, 0, 0.0f);

            } else {
                isExpanded = false;
                // Collapse

                new CollapseAnimation(slidingPanel, panelWidth1,
                        TranslateAnimation.RELATIVE_TO_SELF, 0.65f,
                        TranslateAnimation.RELATIVE_TO_SELF, 0.0f, 0, 0.0f,
                        0, 0.0f);

            }
        }
    });


}
}

custom_layout.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="70dp"
android:orientation="horizontal"
android:layout_marginTop="60dp"
android:background="@drawable/blue_bg">

<ImageView
    android:id="@+id/imageView1"
    android:layout_width="70dp"
    android:layout_height="60dp"
    android:src="@drawable/ic_launcher"
    android:layout_marginLeft="5dp"
    android:layout_marginTop="5dp" />


<LinearLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:layout_marginLeft="10dp"
    android:gravity="left" >


    <TextView
        android:id="@+id/textView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Large Text"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textSize="19sp"
    android:textColor="#ffffff"
    android:textStyle="bold" />


    <TextView
        android:id="@+id/textView2"
        android:layout_width="match_parent"
        android:layout_height="20dp"
        android:text="Tweet body text here"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:layout_marginTop="5dp"
    android:ellipsize="end"
    android:lines="3"
    android:textColor="#ffffff"
    android:textSize="14sp" />


    <TextView
        android:id="@+id/textView3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Small Text"
    android:layout_marginTop="5dp"
    android:textColor="#ffffff"
    android:textSize="12sp" />


</LinearLayout>


</LinearLayout>

CustomAdapter.java

public class CustomAdapter extends ArrayAdapter {
private LayoutInflater inflater;
public CustomAdapter (Activity activity, String[] items){
    super(activity, R.layout.custom_layout, items);
    inflater = activity.getWindow().getLayoutInflater();
}

@Override
public View getView(int position, View convertView, ViewGroup parent){
    return inflater.inflate(R.layout.custom_layout, parent, false);
}
}

我已经设法通过使用以下代码更新获取视图功能使其显示随机颜色但是每次我滚动颜色变化时，我如何使其稳定以便一旦分配颜色它不会改变吗？

 Random rnd = new Random();
    int color = Color.argb(255, rnd.nextInt(256), rnd.nextInt(256), rnd.nextInt(256));

  View rowView = inflater.inflate(R.layout.custom_layout, parent, false);
    rowView.setBackgroundColor(color);

Answer 1

您必须使用带有两个视图的自定义适配器。您可以在适配器的getView 方法中更改左视图的颜色。

Answer 2

按如下方式创建布局文件。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="horizontal" 
    android:weightSum="1">

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:layout_weight="0.3" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:layout_weight="0.7" />

</LinearLayout>

您的 activity class onCreate() 方法应该如下所示。

ListView listView = (ListView) findViewById(R.id.listView1);
String[] Example = new String[] { "Android Introduction",
"Android Setup/Installation", "Android Hello World",
"Android Layouts/Viewgroups", "Android Activity & Lifecycle",
"Intents in Android" };

ArrayList<String> list = (ArrayList<String>) Arrays.asList(Example);
CustomAdapter adapter = new CustomAdapter(this, list);
listView.setAdapter(adapter);

按如下方式创建自定义适配器 class。

public class CustomAdapter extends BaseAdapter {
    Context context;
    ArrayList<String> listOfContents;
    LayoutInflater inflater;

    public CustomAdapter(Context context, ArrayList<String> list) {
        this.context = context;
        listOfContents = list;
        inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        return listOfContents.size();
    }

    @Override
    public Object getItem(int position) {
        return listOfContents.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        convertView = inflater.inflate(R.layout.list_row, null);

        Random rnd = new Random();
        int color = Color.argb(255, rnd.nextInt(256), rnd.nextInt(256),
                rnd.nextInt(256));

        TextView clorText = (TextView) convertView.findViewById(R.id.textView1);
        TextView clorText2 = (TextView) convertView
                .findViewById(R.id.textView2);

        clorText.setBackgroundColor(color);
        clorText2.setBackgroundColor(Color.BLACK);

        return convertView;
    }
}

此代码完全未经测试。您应该对使用 Listview 和自定义适配器以及生成随机颜色有一个大概的了解。

Answer 3

颜色一直在变化，因为列表项被回收，现在当 android 为滚动的特定列表项第二次调用 getView() 方法时，您重新生成颜色值并且它会改变。

由于您可以生成随机颜色，所以您需要做的就是在生成项目后存储颜色，然后重新使用该颜色。

您可以做的是创建一个存储颜色值的数组列表，然后在 getView() 方法中检查特定位置的颜色是否存在于数组列表中。如果是，则使用该颜色，否则生成随机颜色并将其添加到颜色数组列表中。

例如（未经测试的代码，但方法应该相似）

在 getView() 内部：

int color = 0;
if(colorsList.size > position) {
    //This means that the color has already been generated for this position
    color = colorsList.get(position);
} else {
    //Color hasnt been generated for this position.
    color = Color.argb(255, rnd.nextInt(256), rnd.nextInt(256),
            rnd.nextInt(256));
    colorsList.add(color);
}
clorText.setBackgroundColor(color);

Answer 4

最后，我对我的问题得到了以下答案但是我仍然面临这样的问题，即在每个滚动条上颜色都在变化，我希望它们在分配后保持不变，如果有人可以提供帮助的话伟大的。谢谢你们。通过修改 xml 和自定义适配器代码，我将其设为我的 xml 代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_marginTop="70dp"
android:layout_height="70dp"
android:background="@drawable/blue_bg">

<LinearLayout
    android:layout_marginLeft="20dp"
    android:layout_width="345dp"
    android:layout_height="70dp"
    android:background="@drawable/white_bg">
    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="70dp"
        android:layout_height="60dp"
        android:src="@drawable/ic_launcher"
        android:layout_marginLeft="5dp"
        android:layout_marginTop="5dp" />


    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_marginLeft="10dp"
        android:gravity="left" >


        <TextView
            android:id="@+id/textView1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Large Text"
            android:layout_marginTop="10dp"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:textSize="19sp"
            android:textColor="#000000"
            android:textStyle="bold" />


        <TextView
            android:id="@+id/textView2"
            android:layout_width="match_parent"
            android:layout_height="15dp"
            android:text="Tweet body text here"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:layout_marginTop="5dp"
            android:ellipsize="end"
            android:lines="3"
            android:textColor="#000000"
            android:textSize="14sp" />


    </LinearLayout>

</LinearLayout>

</LinearLayout>

修改java代码为如下代码

 Random rnd = new Random();

   int color = Color.argb(255, rnd.nextInt(256), rnd.nextInt(257), rnd.nextInt(258));

  View rowView = inflater.inflate(R.layout.custom_layout, parent, false);
    rowView.setBackgroundColor(color);

android 自定义列表视图实现

android customised Listview implementation

android

listview

android-listview