Question

我是android开发的初学者。我正在尝试制作一个支持横向和纵向图像的布局。例如，如果图像是肖像，那么它周围应该有白色空间，如果图像是风景，那么它将占据图像视图的整个宽度，并且它们都应保持纵横比。我使用json来获取图像从URL和使用数组适配器来扩展listview中的布局当布局膨胀时，线性布局的重量会自动改变我不知道为什么会这样做？应该采取什么方法呢？我使用java缩放图像还是有其他方法？

以下是布局的屏幕截图 First row of the listview Second row pf the listview

注意：您可以看到，在第二个屏幕截图中，第一个线性布局的高度大于第一个屏幕截图中的线性布局（显示用户的个人资料图片）
timelinerowlayout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#ccc"
android:padding="10dp">

<!-- A CardView that contains a TextView -->
<android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:id="@+id/card_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    card_view:cardCornerRadius="5dp">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:weightSum="3">


        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="0.35"
            android:background="@drawable/border">

            <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:padding="10dp">


                <com.makeramen.roundedimageview.RoundedImageView xmlns:app="http://schemas.android.com/apk/res-auto"
                    android:id="@+id/userProfilePicture"
                    android:layout_width="40dp"
                    android:layout_height="match_parent"
                    android:src="@drawable/ppplaceholder"
                    app:riv_border_color="#333333"
                    app:riv_border_width="2dip"
                    app:riv_corner_radius="5dip"
                    app:riv_mutate_background="true"
                    app:riv_oval="true"
                    app:riv_tile_mode="repeat" />


                <TextView
                    android:id="@+id/username"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_centerVertical="true"
                    android:layout_marginLeft="5dp"
                    android:layout_toEndOf="@+id/userProfilePicture"
                    android:layout_toRightOf="@+id/userProfilePicture"
                    android:text="Small Text"
                    android:textAppearance="?android:attr/textAppearanceSmall" />

            </RelativeLayout>

        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1.5">


            <ImageView
                android:id="@+id/userpostimage"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:adjustViewBounds="true"
                android:scaleType="fitCenter"
                android:src="@drawable/bc" />
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1.16">



        </LinearLayout>

    </LinearLayout>

  </android.support.v7.widget.CardView>

</LinearLayout>

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/swipe_refresh_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content">

  <LinearLayout 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"
    android:orientation="vertical"
    tools:context="com.example.gitesh.timeline.MainActivity">

    <ListView
        android:id="@+id/listview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
  </LinearLayout>

</android.support.v4.widget.SwipeRefreshLayout>

MainActivity.java

package com.example.gitesh.timeline;

import android.graphics.Typeface;
import android.os.Bundle;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.widget.AbsListView;
import android.widget.ListView;
import android.widget.Toast;

import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.TextHttpResponseHandler;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import Classes.PostAdapter;
import Classes.posts;
import cz.msebera.android.httpclient.Header;

public class MainActivity extends AppCompatActivity implements SwipeRefreshLayout.OnRefreshListener {
    ListView datalist;
    PostAdapter PostAdapter;
    private SwipeRefreshLayout swipeRefreshLayout;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    datalist = (ListView) findViewById(R.id.listview);
    datalist.setOnScrollListener(new AbsListView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(AbsListView view, int scrollState) {

        }

        @Override
        public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
            if (datalist.getChildAt(0) != null) {
                swipeRefreshLayout.setEnabled(datalist.getFirstVisiblePosition() == 0 && datalist.getChildAt(0).getTop() == 0);
            }
        }
    });
    swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh_layout);
    Typeface cFont = Typeface.createFromAsset(getAssets(), "SAMARN__.TTF");
    Typeface fontAwesome = Typeface.createFromAsset(getAssets(), "fontawesome-webfont.ttf");
    PostAdapter = new PostAdapter(this, R.layout.timelinerowlayout, cFont);
    datalist.setAdapter(PostAdapter);
    swipeRefreshLayout.setOnRefreshListener(this);

    /**
     * Showing Swipe Refresh animation on activity create
     * As animation won't start on onCreate, post runnable is used
     */
    swipeRefreshLayout.post(new Runnable() {
                                @Override
                                public void run() {
                                    swipeRefreshLayout.setRefreshing(true);
                                    bindData();
                                }
                            }
    );


}

/**
 * This method is called when swipe refresh is pulled down
 */
@Override
public void onRefresh() {
    bindData();
}


public void bindData() {


    try {
        AsyncHttpClient client = new AsyncHttpClient(true, 80, 443);
        client.get("http://indianroute.roms4all.com/fetch_post.php", new TextHttpResponseHandler() {
                    @Override
                    public void onSuccess(int statusCode, Header[] headers, String res) {
                        decodeJson(res);

                    }

                    @Override
                    public void onFailure(int statusCode, Header[] headers, String res, Throwable t) {
                        // called when response HTTP status is "4XX" (eg. 401, 403, 404)
                        Toast.makeText(MainActivity.this, "" + res, Toast.LENGTH_SHORT).show();
                    }
                }
        );
    } catch (Exception e) {
        Toast.makeText(MainActivity.this, "" + e.getMessage(), Toast.LENGTH_SHORT).show();
    }


}

private void decodeJson(String result) {
    try {
        swipeRefreshLayout.setRefreshing(true);
        JSONArray jArr = new JSONArray(result);
        String username, story, picture, check_in, userprofilePicture;
        for (int count = 0; count < jArr.length(); count++) {
            JSONObject obj = jArr.getJSONObject(count);
            username = obj.getString("username");
            story = obj.getString("story");
            picture = obj.getString("picture");
            check_in = obj.getString("check_in");
            userprofilePicture = obj.getString("userprofilePicture");
            posts posts = new posts(username, story, picture, check_in, userprofilePicture);
            swipeRefreshLayout.setRefreshing(false);
            PostAdapter.add(posts);
        }

    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
  }


}

PostAdapter.java

package Classes;

import android.content.Context;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.gitesh.timeline.R;
import com.makeramen.roundedimageview.RoundedImageView;
import com.squareup.picasso.Picasso;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by Gitesh on 14-06-2016.
 */
public class PostAdapter extends ArrayAdapter {

List list = new ArrayList();
Typeface samarn;

public PostAdapter(Context context, int resource, Typeface cFont) {
    super(context, resource);
    samarn = cFont;
}

@Override
public void add(Object object) {
    super.add(object);
    list.add(object);
}

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

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

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row;
    row = convertView;
    PostHolder postHolder;


    if (row == null) {
        LayoutInflater layoutInflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        row = layoutInflater.inflate(R.layout.timelinerowlayout, parent, false);
        postHolder = new PostHolder();
        postHolder.username = (TextView) row.findViewById(R.id.username);
        postHolder.userPostImage = (ImageView) row.findViewById(R.id.userpostimage);
        postHolder.userprofilePicture = (RoundedImageView) row.findViewById(R.id.userProfilePicture);
        row.setTag(postHolder);
    } else {
        postHolder = (PostHolder) row.getTag();
    }

    posts posts = (posts) this.getItem(position);
    postHolder.username.setTypeface(samarn);
    postHolder.username.setText(posts.getUsername());
    Picasso.with(getContext()).load(posts.getUserProfilePicture()).placeholder(R.drawable.ppplaceholder).priority(Picasso.Priority.HIGH).into(postHolder.userprofilePicture);
    Picasso.with(getContext()).load(posts.getPictue()).placeholder(R.drawable.postplaceholder).into(postHolder.userPostImage);
    return row;
}

static class PostHolder {
    TextView username;
    ImageView userPostImage;
    com.makeramen.roundedimageview.RoundedImageView userprofilePicture;

}


}

Answer 1

如果您使用水平线性布局（android:orientation="horizontal"），则将宽度设为0dp，如果是垂直线性布局，则将高度设为0dp 然后给孩子的观点加权。

Answer 2

您已定义weight_sum = 3，该布局的内部视图相应地具有权重0.35，1.5和1.16。

0.35 + 1.5 + 1.16 = 3.01

因此，您为内部视图定义的权重总和并不完全等于3

Answer 3

尝试使用此替换您的布局，我已更改布局权重

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#ccc"
android:padding="10dp">

<!-- A CardView that contains a TextView -->
<android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/card_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
card_view:cardCornerRadius="5dp">

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="0"
        android:background="@drawable/border">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="10dp">

            <com.makeramen.roundedimageview.RoundedImageView xmlns:app="http://schemas.android.com/apk/res-auto"
                android:id="@+id/userProfilePicture"
                android:layout_width="40dp"
                android:layout_height="wrap_content"
                android:src="@drawable/ppplaceholder"
                app:riv_border_color="#333333"
                app:riv_border_width="2dip"
                app:riv_corner_radius="5dip"
                app:riv_mutate_background="true"
                app:riv_oval="true"
                app:riv_tile_mode="repeat" />

            <TextView
                android:id="@+id/username"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerVertical="true"
                android:layout_marginLeft="5dp"
                android:layout_toEndOf="@+id/userProfilePicture"
                android:layout_toRightOf="@+id/userProfilePicture"
                android:text="Small Text"
                android:textAppearance="?android:attr/textAppearanceSmall" />

        </RelativeLayout>

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1.3">

        <ImageView
            android:id="@+id/userpostimage"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:adjustViewBounds="true"
            android:scaleType="fitCenter"
            android:src="@drawable/bc" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">
    </LinearLayout>

</LinearLayout>

</android.support.v7.widget.CardView>

</LinearLayout>

线性布局中的权重无法正常工作

3 个答案: