Question

在尝试构建从github获取的项目时，我一直收到此错误。＆＃39; ＆＃39;没有零参数构造函数。 Gradle构建完成，出现1个错误。是构建gradle的东西。我只是想解决一个项目，我不是一个Android或java程序员，所以请耐心等待我。任何帮助将不胜感激。

我一直从logcat -

获取这个uggly消息

class se.mpeople.collapsingtitlelayoutmpeople.CollapsingTitleLayout has no zero argument constructor 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2999)

以下是CollapsingTitleLayout.java文件的一部分。

    package se.mpeople.collapsingtitlelayoutmpeople;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Build;
import android.support.v4.view.ViewCompat;
import android.support.v7.widget.Toolbar;
import android.text.TextPaint;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AnimationUtils;
import android.view.animation.Interpolator;
import android.widget.FrameLayout;



public class CollapsingTitleLayout extends FrameLayout {


    // Pre-JB-MR2 doesn't support HW accelerated canvas scaled text so we will workaround it
    // by using our own texture
    private static final boolean USE_SCALING_TEXTURE = Build.VERSION.SDK_INT < 18;

    private static final boolean DEBUG_DRAW = false;
    private static final Paint DEBUG_DRAW_PAINT;
    static {
        DEBUG_DRAW_PAINT = DEBUG_DRAW ? new Paint() : null;
        if (DEBUG_DRAW_PAINT != null) {
            DEBUG_DRAW_PAINT.setAntiAlias(true);
            DEBUG_DRAW_PAINT.setColor(Color.MAGENTA);
        }
    }

    private Toolbar mToolbar;
    private View mDummyView;

    private float mScrollOffset;

    private final Rect mToolbarContentBounds;

    private float mExpandedMarginLeft;
    private float mExpandedMarginRight;
    private float mExpandedMarginBottom;

    private int mRequestedExpandedTitleTextSize;
    private int mExpandedTitleTextSize;
    private int mCollapsedTitleTextSize;

    private float mExpandedTop;
    private float mCollapsedTop;

    private String mTitle;
    private String mTitleToDraw;
    private boolean mUseTexture;
    private Bitmap mExpandedTitleTexture;

    private float mTextLeft;
    private float mTextRight;
    private float mTextTop;

    private float mScale;

    private final TextPaint mTextPaint;
    private Paint mTexturePaint;

    private Interpolator mTextSizeInterpolator;

    public CollapsingTitleLayout(Context context) {
        this(context, null);
    }

    public CollapsingTitleLayout(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CollapsingTitleLayout(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

Activity_collapsing_title_layout.xml

?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:app="http://schemas.android.com/apk/res-auto"

    xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_height="match_parent"
             android:layout_width="match_parent">

    <!-- Your content, maybe a ListView? -->

    <app.se.mpeople.collapsingtitlelayout.CollapsingTitleLayout
        android:id="@+id/backdrop_toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="@style/TextAppearance.AppCompat.Widget.ActionBar.Title.Inverse"
        app:expandedTextSize="40dp"
        app:expandedMargin="16dp">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_height="?attr/actionBarSize"
            android:layout_width="match_parent" />

    </app.se.mpeople.collapsingtitlelayout.CollapsingTitleLayout>

</FrameLayout>

ANDROID清单

<?xml version="1.0" encoding="utf-8"?>
<manifest package="se.mpeople.collapsingtitlelayoutmpeople"
          xmlns:android="http://schemas.android.com/apk/res/android">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".CollapsingTitleLayout">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
    </application>

</manifest>

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="CollapsingTitleLayout">
        <attr name="expandedMargin" format="reference|dimension" />
        <attr name="expandedMarginStart" format="reference|dimension" />
        <attr name="expandedMarginBottom" format="reference|dimension" />
        <attr name="expandedMarginEnd" format="reference|dimension" />
        <attr name="expandedTextSize" format="reference|dimension" />
        <attr name="collapsedTextSize" format="reference|dimension" />
        <attr name="android:textAppearance" />
        <attr name="textSizeInterpolator" format="reference" />
    </declare-styleable>

    <declare-styleable name="CollapsingTextAppearance">
        <attr name="android:textSize" />
        <attr name="android:textColor" />
    </declare-styleable>

</resources>

摇篮

configurations {
    all*.exclude group: 'com.android.support', module: 'support-v4'
}
apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "se.mpeople.collapsingtitlelayoutmpeople"
        minSdkVersion 16
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.2.0'
    compile 'com.android.support:design:23.2.0'
    compile 'com.android.support:cardview-v7:23.2.0'
    compile 'com.android.support:palette-v7:23.2.0'

}

Answer 1

我相信它试图告诉你添加一个无参数构造函数。

public CollapsingTitleLayout(){}

该对象具有其他构造函数，但它上面没有无值构造函数。

    public CollapsingTitleLayout(Context context) {
    this(context, null);
}

public CollapsingTitleLayout(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
}

public CollapsingTitleLayout(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);

Answer 2

您的父类似乎没有默认构造函数，因此您无法隐式构造函数。

你必须创建至少一个构造函数来调用其中一个超级（...）＆＃39;可能性。

CollapsingTitleLayout没有零参数构造函数

2 个答案: